U.S. Airline Transport Pilot International 

Flight Language Experiences, Report 

3: Language Experiences in Non-Native 

English-Speaking Airspace/Airports

DOT/FAA/AM-10/9

Office of Aerospace Medicine

Washington, DC 20591

OK-10-0077-JAH

O. Veronika Prinzo

Civil Aerospace Medical Institute

Federal Aviation Administration

Oklahoma City, OK 73125

Alan Campbell

Johns Creek, GA 30022

Alfred M. Hendrix 

Ruby Hendrix

HCS Consulting Services

Roswell, NM 88201

May 2010

Final Report

Federal Aviation

Administration
NOTICE

This document is disseminated under the sponsorship 

of the U.S. Department of Transportation in the interest 

of information exchange. The United States Government 

assumes no liability for the contents thereof.

___________

This publication and all Office of Aerospace Medicine 

technical reports are available in full-text from the Civil 

Aerospace Medical Institute’s publications Web site: 

www.faa.gov/library/reports/medical/oamtechreports
i 

Technical Report Documentation Page 

1. Report No. 2. Government Accession No. 3. Recipient's Catalog No. 

DOT/FAA/AM-10/9 

4. Title and Subtitle 5. Report Date 

U.S. Airline Transport Pilot International Flight Language Experiences, May 2010 

Report 3: Language Experiences in Non-Native English-Speaking 

Airspace/Airports 

6. Performing Organization Code 

7. Author(s) 8. Performing Organization Report No. 

Prinzo OV,1 Campbell A, 2 Hendrix A,3 and Hendrix R3 

9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) 

 

11. Contract or Grant No. 

1

FAA Civil Aerospace Medical Institute, P.O. Box 25082 

Oklahoma City, OK 73125 

2

A. Campbell, Johns Creek, GA, 30022 

3

HCS Consulting Service, Roswell, NM 88201 

 

12. Sponsoring Agency name and Address 13. Type of Report and Period Covered 

 

 

 

Office of Aerospace Medicine 

Federal Aviation Administration 

800 Independence Ave., S.W. 

Washington, DC 20591 14. Sponsoring Agency Code 

15. Supplemental Notes 

Work was accomplished under approved task AM-B-06-HRR-516. 

16. Abstract 

In 1998, the International Civil Aviation Organization (ICAO) took a heightened interest in the role of language in airline 

accidents. Its Air Navigation Commission was directed to complete the task of strengthening relevant ICAO provisions 

concerning language requirements. Member states agreed to take steps to ensure air traffic control (ATC) personnel and 

flight crews involved in flight operations in airspace where the use of the English language is required were proficient in 

conducting and comprehending radiotelephony communications in English. Since then, ICAO developed its EnglishLanguage Proficiency requirements (ELP) and urged its members to document their ELP test implementation plans by 

March 8, 2008. Until all ATC personnel and flight crews involved in flight operations obtain a passing level of ELP, the 

language-based problems international pilots face is not known. This report is a compilation of written responses and 

comments by a group of 48 U.S. pilots of their difficulties in international operations who met with interviewers to discuss 

their language experiences flying into countries where English may or may not be the local or national language among its 

radio operators, controllers, and pilots. In this report, the pilots’ responses to questions 31-38 and their comments from 

discussions of those questions with interviewers are presented as a compiled narrative. The pilots’ responses had nine major 

thrusts: (1) Traveling into non-native English-speaking countries can be a positive learning experience leading to 

professional growth and development; (2) English-language proficiency varies from country to country and individual to 

individual; however, problems occur everywhere; (3) Hearing multiple languages on the radio restricts situational awareness 

and diminishes pilots’ expectations as information derived from the party line decreases; (4) Radio protocol is lost in a 

multilingual environment; (5) Whenever communication problems occur, flight deck operations slow down as the flight 

crew diverts attention away from other tasks, so more of their attention is directed to listening to what the controller said; 

(6) Communicating with non-native English-speaking controllers requires more effort and concentration to ensure the 

intent of the controller’s transmission is understood; (7) When off-normal events arise, controllers have difficulty 

communicating in Common English, and pilots have difficulty understanding them; (8) Voice characteristics contribute to 

intelligibility and the ease with which pilots and controllers understand each other; and (9) Advanced avionics such as 

TCAS/CDTI, FMS, and CPDLC/DataCom offer possible solutions to the language barrier.

 

17. Key Words 18. Distribution Statement 

 

 

Communications, ATC Communication, 

Air Traffic Control 

Document is available to the public through the 

Defense Technical Information Center, Ft. Belvoir, VA 

22060; and the National Technical Information 

Service, Springfield, VA 22161 

19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price 

Unclassified Unclassified 40 

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized 

iii 

Acknowledgments

This research was sponsored by the Federal Aviation Administration Flight Technologies and Procedures 

Branch under the direction of William Adams (AFS-430), and the findings were provided to the Data Com 

Human Factors Working Group. It was conducted under the Flight Deck Program Directive / Level of Effort Agreement between the Human Factors Research and Engineering Group (AJP-61), FAA Headquarters 

and the Aerospace Human Factors Division (AAM-500) of the Civil Aerospace Medical Institute. We thank 

American, Continental, Delta, and United Airlines’ personnel who were instrumental in the success of this 

project – especially the 48 U.S. pilots who participated in the interviews. Among these pilots were several 

who participated in the discussions, either shortly after returning from international flights, left immediately 

after the interview to be part of international flight crews, or deadheaded to the company office from other 

states. These pilots exhibited passion for aviation safety and knew the importance their knowledge and expertise held in international flight operations. We cannot thank them enough. We also thank Captain (retired) 

Terry Hanson and Mr. Graham Elliott (AMA-800) for their helpful comments and items for inclusion in the 

interview questions. Finally, we thank the staff at Xyant Technologies for transcribing the many hours of voice 

tapes and written responses into Excel© spreadsheets.

v 

Contents

METHOD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

	 Section 5: Language Experiences in Non-Native English-Speaking Airspace/Airports. . . . . . . . . . . . . . . . . . 4

Q31. List the different non-native English languages you typically hear over your communications 

system during international flights.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Q32. How would you rate your overall non-native English-speaking language experiences during 

these flights? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Q 33. How is your workload affected by your experience with non-native English-speaking 

language differences during a flight?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Q 34. How often do you experience communication problems in non-native English-speaking 

airspace/airports? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Q 35. Of the non-native English-speaking airports that you fly into, do you find the English 

language skills of other pilots and controllers comparable from one country to that of 

another? Please explain.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Q 35a. Do you find that the intelligibility of some non-native English-speaking controllers causes you to 

work harder to understand them? (Think Montreal versus Katmandu or Johannesburg versus 

Dakar.) Use any other examples that you may care to.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Q 35b. What makes some non-native English-speaking controllers’ speech more difficult than others to 

 understand? (e.g., speech rate, pronunciation). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Q36. When flying in a non-native English-speaking country, how often do controllers use ICAO 

standard phraseologies for routine communications to speak to you? . . . . . . . . . . . . . . . . . . . . . . . 15

Q37. When flying in a non-native English-speaking country, how often do controllers use Common 

English for routine communications to speak to you? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Q38a. In general, how much attention is required for you to understand what a non-native 

English-speaking controller is saying in English? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Q38b. What are the most troubling language-based problems you experienced with non-native Englishspeaking controllers?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Q38c. How often have you heard non-native English-speaking controllers use jargon or slang that was 

difficult to interpret? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Q38ci. Please write some examples of the jargon that was difficult to interpret.. . . . . . . . . . . . . . . . . . . . . 25

DISCUSSION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

vii 

EXECUTIVE SUMMARY

This is the third report from series one that presents 

the findings from in-depth interviews with pilots who fly 

internationally for major U.S. air carriers. The first series 

of reports are from small focus group discussions with 

48 U.S. pilots. A second series used the same format and 

questions with pilots flying internationally for Aeroflot, 

Alitalia, China Air, and LAN Chile airlines.

English language proficiency is a safety concern, as 

noted by the International Civil Aviation Organization 

(ICAO 2004). Given that international flight operations 

are increasing, it is important to know more about the 

language experiences U.S. pilots encounter when flying 

into countries where English may or may not be the local or national language among their radio operators, air 

traffic controllers, and pilots. 

Several major U.S. airline companies were asked to 

solicit volunteers from among their international pilots 

to serve as paid subject matter experts in a structured 

interview constructed to assess the language difficulties 

they encounter during international flights. There were 12 

pilots from each of four airlines –American, Continental, 

Delta, and United – for a total of 48 airline transport 

pilots (ATPs). These pilots were assumed to be representative of typical U.S. airline pilots flying internationally as 

to English language proficiency, familiarity with ICAO 

and aviation procedures, terminology, and standard air 

traffic phraseology. We limited the size of each focus 

group to no more than four pilots. There were morning 

and afternoon sessions that took place over several days 

at each company’s preferred location. 

The structured interview was divided into 10 sections: (1) Background Information, (2) Pre-Flight 

Preparation, (3) Air Traffic Control (ATC) Procedures, 

(4) Word Meaning and Pronunciation , (5) Language 

Experiences in Non-Native English-Speaking Airspace/

Airports, (6) Non-Native English-Speaking Controllers 

Communicating With Native English-Speaking Pilots, 

(7) Language Experiences in Native English-Speaking 

Airspace/Airports, (8) Native English-Speaking Controllers Communicating with Non-Native English-Speaking 

Pilots, (9) Communication Problems, and (10) Technological Intervention. A copy of the interview questions is 

included in the first report (Prinzo & Campbell, 2008).

The first report summarized the U.S. pilots’ oral and 

written responses to the questions contained in Sections 

1-3, and the second report continued with Section 4. This 

report continues with Section 5 and summarizes the pilots’ 

responses to questions 31-38. It provides a wealth of ideas 

related to the international flight experiences of the pilots 

who participated in small focus group discussions. The 

pilots’ answers to the questions and discussions during 

the interviews were their perception of the situations they 

encountered. Many stories were anecdotal and some were 

relayed in third person. The analyses of those discussions 

and written responses are summarized and presented as if 

from one pilot’s diary containing a compendium of flight 

experiences. This was done to preserve the richness and 

integrity of the information given during the interviews. 

The pilots listed 21 different non-native English languages that they heard during their international flights, 

with Spanish and French listed 22.60% and 19.86%, 

respectively. When asked about their overall non-native 

English-speaking language experiences, 52% reported it 

as negative, while only 25% indicated they rarely experienced communication problems. 

When flying in a non-native English-speaking country, 

41 of 48 of the pilots indicated that 75% or more of their 

interactions with controllers involved the use of ICAO 

standard phraseology during routine communications. 

Only 25% of the pilots reported controllers frequently 

switch from ICAO standard phraseology to Common 

English when trying to explain or verify a previously 

issued clearance. Although these controllers’ Common 

English might be unconventional, they made their point. 

They said many controllers avoid saying anything considered nonstandard. They believe this to be because of 

the controller’s limited English skills. In fact, 65% of the 

pilots said that a considerable amount or more of their 

attention was required to understand the English spoken 

by non-native speakers. 

The pilots’ responses had nine major thrusts: 

1. Traveling into non-native English-speaking countries 

can be a positive learning experience leading to professional growth and development, 

2. English language proficiency varies from country 

to country, and individual to individual; however, 

problems occur everywhere,

3. Hearing multiple languages on the radio restricts situational awareness and diminishes pilots’ expectations 

as information derived from the party line decreases, 

4. Radio protocol is lost in a multilingual environment,

5. Whenever communication problems occur, flight deck 

operations slow down as the flight crew diverts attention away from other tasks so more of their attention 

is directed to listening to what the controller said,

6. Communicating with non-native English-speaking 

controllers requires more effort and concentration 

to ensure the intent of the controller’s transmission 

is understood,

7. When off-normal events arise, controllers have difficulty communicating in Common English, and 

pilots have difficulty understanding them,

8. Voice characteristics such as accent, pitch, pronunciation, and speech rate each contribute to intelligibility 

and the ease with which pilots and controllers understand each other, and

9. Advanced avionics such as TCAS/CDTI, FMS, and 

CPDLC/DataCom offer possible solutions to the 

language barrier.

1 

United States Airline Transport Pilot

International Flight Language Experiences

Language is the source of misunderstandings.

— Antoine de Saunt-Exupéry in The Little Prince

In a report released by the National Bureau of Economic Research (NBER, 2008), America’s economy has 

been in recession since December 2007. Since then, other 

countries have reported economic downturns indicating 

the existence of a global recession. The U.S. is working 

diligently with other countries to limit its effects both 

within the U.S. and internationally. In light of this recession, the Federal Aviation Administration (FAA) updated 

its projections in the number of passengers arriving into 

and departing from the U.S. through the year 2025 (FAA 

2008a). That report notes, “The worldwide recession 

drives international passengers down 0.9 percent in 2009 

but a rebound in economic growth leads to a 4.2 percent 

growth in passengers in 2010. For the balance of the 

forecast period, stable worldwide economic growth leads 

to international passenger growth averaging 4.6 percent 

a year, and totaling 310.0 million in 2025” (p35). As 

shown in Figure 1, the largest percentage of growth will 

involve the Asia/Pacific area, followed by the Atlantic. 

Once the volume of U.S. and foreign flagship carriers 

increases, so will the number of transmissions necessary to 

provide air traffic control (ATC) services. These services 

include clearances and instructions, as well as traffic and 

weather advisories, reports, and requests. Given that the 

present air-ground communications system is reaching 

pre-9/11 saturation levels during peak traffic periods, it 

is common for some controllers to send longer and more 

complex messages to reduce the number of times they need 

to communicate with individual aircraft (Prinzo, Hendrix, 

& Hendrix, 2006) and use nonstandard phraseology to 

decrease the amount of time on frequency (e.g., go fast). 

The ability to quickly decode, understand, read back, 

and comply with these messages can be a problem for all 

pilots, especially those who are unfamiliar with how ATC 

services are delivered by controllers in a particular region. 

Airline transport pilots (ATPs) who have English as 

their second or third language may have difficulty understanding local nuances and lengthy clearances delivered at 

rapid rates. Likewise, native English-speaking pilots may 

encounter difficulties understanding the English spoken 

by English-speaking controllers or by non-native speakers 

of English. Reports from Brazil in recent months have 

pointed increasingly at controller error as the leading 

likely cause of an accident involving a Legacy business 

jet and a Boeing 737 that resulted in the death of 154 

people in 2006. Accident transcripts revealed that the 

business jet pilots apparently had trouble understanding 

the English spoken by the Brazilian controllers. On three 

separate occasions, they asked for clarification without 

receiving a satisfactory response (Associated Press, 2007). 

The final accident report issued by Centro de Investigação 

e Prevenção de Acidentes Aeronáuticos (CENIPA) and 

National Transportation Safety Board (NTSB) concur 

with each other on many of the basic facts and findings; 

however, they disagree in their interpretations of these 

facts and offer different conclusions. Whereas CENIPA 

U.S. & FOREIGN FLAG CARRIERS

 PASSENGER TO/FROM THE U.S. 

2008 - 2025

4 4.3

5.2

3.2

0.0

2.0

4.0

6.0

Atlantic Latin America Asia/Pacific Canada

Transborder

Annual Percentage Growth

Figure 1. Projected Average Annual Growth in Passengers 
2 

attributes the accident to mistakes made by the pilots 

and controllers, NTSB places the fault upon the controllers and the ATC system. Appendix 1 of that report 

contains the following probable causes issued by NTSB 

(CENIPA, 2008).

The evidence collected during this investigation 

strongly supports the conclusion that this accident 

was caused by N600XL and GLO1907 following 

ATC clearances which directed them to operate in 

opposite directions on the same airway at the same 

altitude resulting in a midair collision.

The loss of effective air traffic control was not 

the result of a single error, but of a combination of 

numerous individual and institutional ATC factors, 

which reflected systemic shortcomings in emphasis 

on positive air traffic control concepts.

Contributing to this accident was the undetected 

loss of functionality of the airborne collision avoidance system technology as a result of the inadvertent 

inactivation of the transponder on board N600XL.

Further contributing to the accident was inadequate 

communication between ATC and the N600XL flight 

crew.

These findings are relevant to a recent content analysis 

of the communication between Thai controllers and 

local Thai pilots, native English (e.g., U.S., British) and 

non-native English-speaking (e.g., Korean, Japanese) 

pilots performed by Tiewtrakul (2007). The results of 

that study found that the local Thai ATC accent affected 

pilot understanding. In particular, there were more 

communication problems (readback errors, requests 

for repeats, and no responses) among the non-native 

English-speaking pilots, followed by native Englishspeaking pilots, and the least problems occurred among 

the Thai/local pilots. Tiewtrakul concluded that the Thai 

controller’s native language may have influenced their 

English pronunciation to the point that non–native Thai 

speaking pilots were at a disadvantage in understanding 

what was spoken.

Likewise, controllers may have difficulty understanding the English spoken by native and non-native 

English-speaking pilots. For example, Kanu Gohain, 

Director General of Civil Aviation (DCGA) in India, 

told reporters that in 2006 India “sent home” between 

20-25 pilots (mainly from the Commonwealth of 

Independent States and Eastern Europe) because their 

English posed safety concerns (Reuters, 2007). The 

DGCA did not clear these foreign pilots to fly in India 

because they did not demonstrate proficiency in English 

on the oral exams.

A content analysis of U.S. ATC communications 

performed by Prinzo, Hendrix, and Hendrix (2008) 

revealed that when an aircraft was operated by foreign 

carrier/airline with a language other than English as 

their primary or official language, not only was more 

time spent on the radio communicating with ATC, 

but more transmissions were exchanged, and more 

communication problems were present within their 

transactions. In these situations, the pilot’s English 

proficiency – especially accents – often resulted in the 

controller not being able to completely understand the 

pilot. Rarely did the U.S. controllers express difficulty 

understanding an English-speaking pilot.

Lack of proficiency in the English language among 

pilots and controllers who are non-native English speakers has resulted in fatalities,1

 mishaps, and unsafe acts. In 

response, the International Civil Aviation Organization 

(ICAO), an agency of the United Nations, published 

in 2004 the Manual on the Implementation of ICAO 

Language Proficiency Requirements. The implementation of the ICAO language proficiency requirement 

was slated for March 2008.2

 Specifically, “Aeroplane 

and helicopter pilots and those flight navigators who 

are required to use the radio aboard an aircraft shall 

demonstrate the ability to speak and understand the 

language used for radiotelephony communications.”3 

Similarly, “Air traffic controllers and aeronautical station operators shall demonstrate the ability to speak 

and understand the language used for radiotelephony 

communications.”4 

English language proficiency educational materials, 

training programs, and testing programs are being developed and implemented to meet the ICAO mandate. 

Clearly, the concern for aviation safety continues to 

be a global concern. Given that what is known about 

language-based communication problems is derived 

from accident, incident, and mishap reports, what 

is absent is an understanding of how prevalent these 

problems are during normal air traffic operations.

The available reports that describe operational communications between pilots and U.S. controllers were 

derived from voice tapes provided by tower (Cardosi, 

1994; Burki-Cohen, 1995), terminal radar approach 

control (Cardosi, Brett, & Han, 1996; Prinzo, 1996), 

and air route traffic control centers (Cardosi, 1993). 

Unfortunately, the existing reports (written a decade 

ago) do not provide any indication as to the magnitude or severity of communication problems that 

involve non-native English-speaking pilots who fly 

international flagships into the U.S. or by U.S. pilots 

who fly to international destinations. Consequently, 

an operational shortfall exists in our understanding of 

international operational communications as it occurs 

within the National Airspace System (NAS) and in 

foreign countries and its perceived impact on safety by 

airline transport pilots.

1 As an example, in 1990, Avianca Flight 52 was making its third approach into 

JFK Airport and failed to inform air traffic control they had a fuel emergency 

and crashed.

2 In November 2007, the Assembly of ICAO drafted a resolution to precede 

Resolution A32-16 that would urge up to a 3-yr extension of the provisions 

in A32-16 and Article 40 of the Convention.

3 Manual on the Implementation of ICAO Language Proficiency Requirements, Appendix A.

4 Ibid.
3 

Likewise, there is a lack of baseline data regarding 

the flight experiences of pilots who fly internationally. 

It comes as no surprise then that research is needed to 

identify and fill the gaps in communications data that 

would contribute to the understanding of some of the 

language issues, communication problems, and procedural differences airline transport pilots encounter when 

flying internationally. As digital voice communications 

systems and their applications emerge, it is important 

to know which messages may present a problem for 

non-native English-speaking pilots.

Therefore, the purpose of this study was to identify 

language issues that can become barriers to efficient and 

effective communication between the airline transport 

pilots (one group of native-English speaking pilots, one 

group of non-native English-speaking pilots) and air 

traffic controllers (who may or may not be fluent in 

English). A total of 64 international airline transport 

pilots participated in small focus group meetings to 

discuss the types of communication problems they 

encounter during international flights. There were 48 

pilots who flew for four U.S. air carriers and 12 pilots 

who flew for four foreign air carriers. The U.S. pilots 

were interviewed separately from the foreign pilots.

We attempted to preserve the richness and breadth of 

the information given during the interviews in a series 

of reports. The first report (Prinzo & Campbell, 2008) 

provided an analysis of the first three sections of the 

structured interview: 1) Background Information related 

to the recency of international flight experiences among 

the pilot-participants, 2) General/Preflight Preparation, 

and 3) Air Traffic Control (ATC) Procedures. It covered 

the U.S. pilots’ responses and discussions of questions 

1-23. The second report (Prinzo, Campbell, Hendrix, 

& Hendrix, 2010) is a continuation of the analysis of 

the U.S. pilots’ flight experiences during times when 

they experienced language issues that became a barrier 

to efficient and effective communication involving word 

meanings and pronunciation. It covered the pilots’ responses and discussions to questions 24-30 in Section 4. 

This is the third report in the series. It involves pilots’ 

responses and discussions of questions 31-38 found in 

Section 5 and centers upon their language experiences 

in non-native English-speaking airspace and airports. 

When possible, the content was tabulated and presented 

in tables. Their verbal discussions are combined, condensed, edited, and presented from the perspective of 

a hypothetical, albeit typical ATP-rated pilot, in the 

form of a narrative. Pilots were to imagine flying into 

a country where a language other than English was the 

primary language. Although the controller would speak 

English to them, the controllers might speak to other 

local pilots in the primary language of their country. 

As a result, the U.S. pilots might hear several different 

languages on any given frequency.

METHOD

Participants

A total of 48 U.S. pilots (12 pilots each from American, 

Continental, Delta, and United Airlines) participated in 

this study. All were selected by their respective companies 

and received remuneration from Acheson Consulting for 

their participation as paid subject matter experts. U.S. 

pilots flew an average of 15 yrs internationally (S.D. = 

10 yrs, range = 1-36 yrs) and had an average of five international flights (S.D. = 6 flights, range = 0-35 flights) 

in the 30 days preceding the interviews. 

Structured Interview Questionnaire

Pilots provided information pertaining to any problematic English language-based communication, procedure, or observation they experienced or heard over their 

aircraft’s communications system during international 

flights. The questions were developed by the first author, 

with expertise provided by several retired airline transport 

pilots, a member of the Proficiency Requirements in 

Common English Study Group (PRICESG), and several 

human factors research psychologists. The Questionnaire 

Construction Manual (Babbitt &Nystrom, 1989) was 

used to construct some of the questions and response 

alternatives. 

A copy of the questionnaire was administered during 

a mock interview with three FAA employees who had 

international piloting experience. During that meeting, 

participants commented on the understandability of 

individual items and critiqued the breadth, structure, 

and scope of the questionnaire as a whole. Their comments were incorporated into the final revision of the 

questionnaire.

The structured interview questionnaire was divided 

into 10 sections, with a total of 64 questions (q): (1) 

Background Information (q1-17); (2) General/Pre-Flight 

Preparation (q18); (3) ATC Procedures (q19-23); (4) 

Word Meaning and Pronunciation (q24-30); (5) Language 

Experiences in Non-Native English-Speaking Airspace/

Airports (q31-38); (6) Non-Native English-Speaking 

Controllers Communicating With Native EnglishSpeaking Pilots (q39-45); (7) Language Experiences in 

Native English-Speaking Airspace/Airports (q46-53); (8) 

Native English-Speaking Controllers Communicating 

With Non-Native English-Speaking Pilots (q54-59); (9) 

Communication Problems (q60-62); and (10) Technological Intervention (q63-64).

Procedure

Within two weeks of the scheduled interview, each 

pilot received a copy of the interview protocol and 

questionnaire. They were asked to respond to a set of 

language-based questions regarding their international 

flight experiences and consent to being audio recorded. 

If they agreed to participate in the structured interviews, 

they were to complete the 17-page questionnaire and 
4 

return their responses to their airline’s designated point of 

contact. Their responses were copied and made available 

to the interviewers for review prior to the interviews. The 

pilots had access to their completed questionnaires to aid 

the interview process. The interviews were conducted at 

the pilots’ airline office in the U.S.

There were no more than four pilots in each focus group, 

and each meeting with U.S. pilots lasted approximately 

3.5 hrs. Upon completion of the interviews, the pilots’ 

written responses and oral remarks were transcribed and 

incorporated into a database, along with the responses 

and remarks of the other pilot participants for analysis.

RESULTS

Some of the pilot discussions of a particular question 

appeared to address similar topics with an underlying issue or concern. Consequently, those topics were grouped 

together and its core issue, or concern, extracted and 

labeled. Topics within an issue or concern are presented 

alphabetically, as is the issue or concern. The pilots’ responses were edited to remove redundancies and improve 

readability.

Forty-eight ATP pilots responded to the questions 

and reported English as their primary language, having learned it informally at home. Approximately 60% 

reported they neither spoke nor understood languages 

other than English. Many of the remaining U.S. pilots 

indicated they spoke/understood some French, Spanish, 

or both. In addition to Spanish, one pilot spoke/understood German, and another spoke/understood Spanish, 

French, and Portuguese. The pilots made 77 flights to 

32 different countries – 14 countries were flown to once 

each while six flights were made to Chile. All continents 

except Antarctica are represented. 

Section 5: Language Experiences in Non-Native 

English-Speaking Airspace/Airports

31. List the different non-native English languages you 

typically hear over your communications system during international flights.

When asked to list the different non-native English 

languages heard over their communications system, one 

respondent stated, “I hear all local languages while flying 

through every country I passed,” but gave no specific 

language; while another reported “None.” The other 

46 respondents made 146 entries. The languages were 

grouped according to how often they were listed and then 

converted into percentages.

As seen in Table 1, pilots listed 21 different languages; 

Spanish and French were cited 22.60% and 19.86% 

respectively. Chinese, German, Italian, Japanese, Portuguese, and Russian were listed between 6.16% and 8.90%. 

The remaining languages varied from 0.68%.to 2.74%.

32. How would you rate your overall non-native Englishspeaking language experiences during these flights? 

As seen in Table 2, slightly more than 52% of the pilots 

reported negative experiences, while only 17% reported 

either very positive or positive experiences during overseas 

flights. The remaining 31% reported their non-native 

English-speaking experiences as neutral.

Very Positive Explanation

Of the two respondents, one offered comments. 

Not All Air Traffic Control Messages Are in English

Someone asked me why I didn’t speak French when 

in France because I spent so much time there. I said, 

“One, because where we travel I would have to learn 

to speak Spanish, Portuguese, French, German, Swiss, 

Japan and Russian. And two, the ICAO standard is 

Table 1. Non-Native English Languages Typically Heard During International Flights. 

Non-Native English Language Percentage Cited 

Cited Between 29 - 33 Times 

Spanish 22.60 % 

French 19.86 % 

Cited Between 9 – 13 Times 

German, Portuguese 8.90 % 

Japanese 7.53 % 

Chinese 6.85 % 

Italian, Russian 6.16 % 

Cited Between 1 – 4 Times 

Dutch 2.74 % 

Arabic 2.05 % 

Korean 1.37 % 

Danish, Hebrew, Hindi, Hispanic, Mandarin Chinese, Papiamento,a

Swiss, Taiwanese, Turkish, Vietnamese 0.68 % 

Total 100.00 %*

aPapiamento is the local language (a mixture of four unrelated languages) of Curacao, the largest and 

most populous island of the Netherlands Antilles. 

*

Allowing for rounding error 
5 

English. It could have been French, Spanish, or German; but it’s English."

Positive Explanation

Six respondents rated their overall non-native Englishspeaking language experiences during these flights as 

positive. Approximately 67% of them provided comments 

that were edited, compiled, grouped, and are presented 

alphabetically.

Kudos for English Speakers

I’m so impressed that everyone can speak our 

language so much better than I can speak theirs. For 

many, it’s a second job. They’re working in the middle 

of the night when we’re going there. English is a 

second language for them, so we need to understand 

what they’re going through. It can be inconvenient 

for them when we ask for a clearance two or three 

times, but overall they do a pretty good job. I have 

to add, English is supposed to be the international air 

traffic language; and we have a ways to go in other 

parts of the world in making that happen. 

Because they speak in another language [to local 

pilots], we don’t really know what these other airplanes are doing. Other than the loss of situational 

awareness, which is really a big deal when we get 

into the approach phase, it’s not so bad. I took several years of Spanish, so I can pick up mostly what 

they’re saying because they’re using ATC Spanish. 

So overall, it becomes a learning experience and my 

understanding improves.

High-Pitched Voices Are Difficult to Understand

We encounter difficulties in Taiwan until we get 

on approach and tower. I have a difficult time understanding the clearances issued by controllers in 

Bangkok and clearance delivery can be very challenging for me. I also have difficulty understanding 

several Japanese enroute controllers who have very 

high, nasally voices. I almost anticipate what they’re 

going to say, and read back what I thought they would 

say; and they either say my read back was correct 

or not correct.

Neutral Explanation

Fifteen respondents rated their overall non-native 

English-speaking language experiences during these flights 

as neutral. Approximately 40% of them provided comments (written and interview) that were edited, compiled, 

grouped, and are presented alphabetically.

ATC Separation Versus TCAS

A lot of folks come to me with stories – “I was in 

holding and there was an aircraft below me and 

ATC was trying to clear me down into that aircraft. 

I told him ‘I got this guy on TCAS.’ Some controllers 

might not know what TCAS is, especially if you say 

it that way.” The pilot could not get the point across 

that he was not going to descend. There was an airplane below him. ATC kept giving him a clearance 

to descend down to 4,000 feet. Some controllers are 

not going to say they don’t understand what you’re 

saying; and my point is – and it’s not a huge point – 

there’s stuff on either side.

Culture

It certainly seems like we’re unearthing the “Ugly 

American,” and that our perspective tends to be 

on problems communicating or flying within their 

airspace. I expect there will be some difficulties 

and understanding what’s going on when I go there. 

Over a period of time, it seems less of a problem. I 

still find some difficulty understanding what they’re 

saying but some is good, some is poor; and the poor 

is really poor.

It Depends on How We Interpret the Question

I look at it as a learning experience in a dynamic 

environment – taken one case at a time – it’s negative. 

Taken over time, it becomes a learning experience; 

and learning experiences are positive.

Table 2. Pilot Ratings of Non-Native English-Speaking Language Experiences. 

Overall Non-Native English 

Language Experience 

Number 

of Pilots Issues Discussed 

Very Positive 2 Not All Air Traffic Control Messages Are in English 

Positive 6 Kudos for English Speakers 

High-Pitched Voices Are Difficult to Understand 

Neutral 15 

ATC Separation Versus TCASa

Culture 

It Depends on How We Interpret the Question 

Reduces Situational Awareness 

Speech Rate 

Negative 25 

Cultures Differ 

Increases Workload 

Multi-Linguistic Environments Reduce Situational Awareness 

Radio Protocol Is Lost in a Multi-Linguistic Environment 

aTraffic Alert and Collision Avoidance System 
6 

Reduced Situational Awareness

I’m only negative when controllers and pilots talk 

to each other in their native language. If it’s a lower 

altitude on arrival or departure frequencies and it’s 

at a very busy time, they’re taking away from me part 

of the situational awareness where I know where that 

airplane is. If he was talking to the one 10 miles out 

when he cleared the plane to land, I would like to 

know if the guy that he’s talking to is on arrival and 

is 10 miles out. However, if they’re talking in Spanish 

or Portuguese, I’m denied that piece of information.

Speech Rate

It’s an interesting thing – we go there with the attitude of some speak English better than others do. 

We’re going to do our best to get from Point A to Point 

B safely and check all the boxes. When we call for 

clearances, we talk slowly and hope they return the 

courtesy by speaking slowly so we can understand 

them and write it all down.

Negative Explanation

Twenty-five respondents rated their overall non-native 

English-speaking language experiences during these flights 

as negative. Approximately 40% provided comments 

that were edited, compiled, grouped, and are presented 

alphabetically.

Cultures Differ

It’s a given we’ll have some issues with the language 

barrier. I don’t like it when controllers speak in their 

native language because it is to our detriment, since 

it can impact situational awareness – especially when 

there is an airplane we need to be concerned about 

in our airspace. If there is a problem or something we 

need to be aware of, at times they don’t answer. So 

that’s where datalink may help – when we’re trying 

to get other information that they just don’t know 

how else to convey.

Controllers in some countries refuse to use anything 

except English. I have heard some controllers specifically chide pilots for not using English. 

Increases Workload

More effort is required to assure understanding 

combined with busy radio frequencies means that 

other tasks get delayed. It increases the number of 

times clearances will have to be repeated. It adds to 

the controller’s workload and the pilot’s also.

Multi-Linguistic Environments Reduce 

Situational Awareness

We hear controllers and pilots use their native 

language for conversation – as we do domestically. 

It perplexes me when I hear things that I do not understand. First of all, it eats up airtime that somebody 

else may need. Second, it distracts me away from my 

situational awareness. I was in China this weekend, 

and most of the other airplanes were getting their 

clearances in Chinese; in Germany, I only hear clearances in English. If ATC is talking to Air France, it’s in 

French. I’d really like to know what their clearances 

were, but I don’t speak the local language. I have 

no idea where they are or what they’re doing. They 

may be talking about a thunderstorm up ahead, and 

we’re heading there. 

Radio Protocol Is Lost in a Multi-Linguistic 

Environment

The other problem is that it breaks radio decorum 

– the unwritten rules of when to chime in. If ATC 

talks to Air France in French, I’m waiting for the pilot 

to respond. I don’t know whether this guy should 

respond back or not. I thought that after counting off 

a few seconds enough time passed so I’m going to 

ask to do something, but I just stepped on top of Air 

France, because now he’s trying to respond.

33. How is your workload affected by your experience with non-native English-speaking language 

differences during a flight?

In response to this question, one respondent offered no 

comments while another reported no affect on his workload. Among the remaining pilots, 48% said it increased 

their workload, 37% said it was workload-related, and 

15% said it required added attention. Their responses 

were organized according to how their workload was 

affected, and the issues gleaned from their responses are 

presented in Table 3.

Increases Workload

Added Repeats and Requests

I find myself repeating requests or passing on 

information. I might give up on a request because 

it creates too much confusion and the workload increases when I make repeated radio calls to clarify 

ATC instructions. So, I sit there and I’m keyed into 

what’s coming out, trying to decode what I received, 

especially when another crewmember says, “What 

did he say?” If I have to control it for him – I have to 

go back and talk to the controllers again, transmissions double.

Communication Intensified

My workload typically increases when I enter a foreign country because, in addition to keeping track of 

what my airplane’s doing, I spend extra time making 

sure I understand what ATC is telling me to do. I am 

more alert, vigilant, and cognizant of what I think 

was said, determine if it jives with what I expected 

to hear but at the same time I don’t want to read into 

it. If I don’t understand, I ask again to get it clarified. 

The extra attention requires increased concentration 

on communication and being distracted from normal 

cockpit duties. I would like to know what the controllers are saying to the other aircraft – especially in an 

approach environment. If ATC clears the guy ahead 
7 

of us to a certain flight level or altitude, I expect the 

same thing if we’re following. If I don’t understand 

the local language, my situational awareness is degraded because I don’t understand what’s going on 

around me – that is a negative. 

I listen more intently for English messages when they 

are mixed in with other languages. Hearing different 

dialects, tone, accents, pronunciation, and speech 

rate make it fatiguing. With time, my ear becomes 

trained to listen through the accents. If I understand 

the phraseology, I know when a point may come to 

an end; otherwise, I have to listen more intently to 

discern when the next English communication will 

show up.

More Time on Radio

On any trip into a non-native English area, you 

spend extra time on the radios to make sure you 

are not miscommunicating. The workload can be 

tremendous if you don’t understand what is being 

said. It can increase radio chatter, tie up the frequencies, and slow communication down a whole lot.

Non-Native English Speaker Ability

The ability of the non-native English speaker is the 

big factor in understanding what ATC wants us to do. 

If we get a controller who doesn’t speak English very 

well, workload goes up when some crewmembers 

have difficulty communicating and understanding 

ATC. Miscommunication is the thing that I worry 

about most, and we’re always on guard for it. Many 

times flying from Brussels to London, we go into a 

holding pattern and as communications increase 

because of the intensity of the operation, CRM5

 goes 

down because the pilot-flying has to answer the radio 

at the same time. 

To Maintain Situational Awareness

Workload increases because we lose situational 

awareness when pilots and controllers speak in their 

native tongue. Half the focus of the non-English 

portions is to glean possible traffic conflict informa5 Cockpit Resource Management

tion. We’ve got to be more aware of the situation 

outside – there are airplanes on the TCAS. The crew 

is looking out the window, keeping an ear open for 

somebody else that ATC is speaking to in English that 

could give us a better picture of what’s going on out 

there. It’s a bit distracting not to have a sense of what 

other planes are doing. We spend more time trying 

to figure out who, what, where, why, and where they 

are at, and how they’re affecting our flight.

Requires Added Attention

It Is Easy to Miss Your Call Sign

A lot of times I’ll miss a radio call because I didn’t 

hear my call sign because I wasn’t able to follow 

the communications directed in the local language 

to other air traffic around me. Other pilots may get 

clearances either in a native language or in an accent that I’m unable to understand. I might miss a 

call because I don’t realize that’s what they’re doing.

I’ll be honest with you – if we went to an entirely 

digital or database system, even in domestic control, we wouldn’t be able to use that either because 

we would never see the clearances going to other 

aircraft. If someone was given a descent, or a slow 

down electronically, we would never see it; and we 

use that domestically here. I use that information 

for planning – well that guy just got slowed down; 

maybe I should ask for slower so I don’t have to hold 

on arrival and burn extra gas. It’s more difficult to 

keep a high awareness of the traffic in two-language 

radio transmissions.

Multiple Languages On Frequency

I listen to all radio transmissions. It is distracting 

because I have to listen harder whether he’s talking 

to me in English or another airplane in a foreign 

language. If I’m concentrating on that, maybe I’m not 

concentrating on what normally gets my attention. 

This is pretty much a mundane point; however, it 

does increase our workload. For example, I am on 

approach and there’s an aircraft right in front of me. 

If ATC switches him to the tower and gives the frequency in English, I know what he’ll give me. But if 

it’s in French, it just increased my workload – I have 

Table 3. How Pilot Workload Is Affected During Flights by Non-Native EnglishSpeaking Languages. 

How Workload Is Affected Issues Discussed 

Increases Workload (n=22) 

Added Repeats and Requests 

Communication Intensified 

More Time on Radio 

Non-Native English Speaker Ability 

To Maintain Situational Awareness 

Requires Added Attention (n=7) 

It is Easy to Miss Your Call Sign 

Multiple Languages On Frequency 

Pronunciation of Fixes and Nonstandard Terms 

Speech Rate and Dialect 

Workload Related (n=17) 

Emergency 

Must be Prepared 

Unfamiliar Airports 

Use of Electronic Equipment 
8 

to work faster, for I can’t preemptively set it in and 

be ready when I’m switched over to tower.

When controllers talk in their language, it’s invariably when there’s a lot going on. They revert to their 

language because the pilots don’t understand what 

to do when it’s said in English. I get the impression 

they want to get the pilots off their backs.

I tend to listen to ATIS6

 twice as long. The first part 

is in the native language and the second is English. 

It is not unusual to turn the radio off for the first part 

and by the time you turn it back on, it’s in the native 

language again.

Pronunciation of Fixes and Nonstandard Terms

When we ask for something that’s not standard, our 

workload increases in a million places. I fly a glass 

cockpit triple seven.7

 When ATC gives me something 

that’s not on the display, I pull out the charts. I must 

verify the waypoints so I can put them in the FMS8

 – 

where is that fix? Where are they sending me? Spell 

the fix and I’m out of your way. 

There are things that we do to mitigate the increased 

workload. We went so far as to make a four-page list 

of Spanish words – what the fixes are; the way they’re 

spelled; the way they sound – the way controllers 

pronounce them and the way we hear them.

Speech Rate and Dialect

I have to pay more attention because of the speed 

of the message that is passed to me. Also, the tone 

and dialect – it is more fatiguing.

Workload Related

Emergency

Workload definitely increases, although it’s not 

unsafe by any means. Then again, how would I tell 

the controller I had a cabin fire, engine fire, terrorist 

attack, or something like that in English? If something 

is dangerous or urgent and language is a barrier – it 

could be a problem. On a normal routine basis, it 

increases your workload. Just trying to be prepared 

has an effect on your performance.

Unfamiliar Airports

When we go into certain cities, we fly a normal 

pattern. They may have 15 corridors when we usually 

have two, three, or five – just because of the way we 

come in from the north, or east, or west – it’s usually 

on a track. For some reason they want to bring us in 

on a different waypoint – well, where is it? We dig 

out the chart to find out the difference.

If Lufthansa was flying to Dallas from Frankfurt all 

the time, they would be coming in over the northeast 

corner post. If ATC said to go to a different arrival 

fix such as Bowie, the pilots would not know where 

6 Automated Terminal Information Service

7 Boeing 777 aircraft

8 Flight Management System

it was unless they looked at the chart. If they’re not 

familiar with the area, will they know how the Bowie 

VOR9

 is spelled? 

Must be Prepared

If I’m in an area where I have little experience or 

I am not prepared properly, my workload definitely 

goes up. If I have experience and the controllers come 

back with what we are expecting – our workload 

comes back to what we would consider normal, 

which would be like a 73710 taking off from Denver 

and going to Chicago.

Use of Electronic Equipment

In any dense airspace, we use TCAS a lot; it’s our 

only real backup to not being able to be clear with 

what’s on the radio with the language barrier. The 

Chinese and the cargo carriers aren’t required to have 

TCAS; so there are a lot of airplanes that do not show 

up on it. In the Pacific, we know there is 10 minutes 

between airplanes. We use TCAS to determine when 

to ask for climbs, because we know that ATC won’t 

give it without the 10 minutes. So we might slow to 

get some spacing, and then ask for it. 

I can add to the PDCs11 and ATIS – if we could get 

Datalink messages over the ACARS12 it would be a lot 

simpler. Almost anywhere, domestically, you request 

your PDC or the ATIS, and print it off. Anywhere 

overseas that I’ve been, you’ve got to listen to it.

34. How often do you experience communication 

problems in non-native English-speaking airspace/

airports? 

As shown in Table 4, 25% of the pilots reported in nonnative English-speaking airspace/airports they “rarely” 

experienced communication problems and 52% reported 

“occasionally.” The 11 remaining pilots indicated “at 

least 25% or more of their interactions with non-native 

English-speaking controllers resulted in communications 

problems.” Approximately 40% provided examples of the 

types of problems they experienced.

During the interviews, a pilot was asked whether there 

should be a policy that all countries’ air traffic communication be spoken in English, even to their own pilots. 

The pilot provided the following insight.

Yes, I’d vote for it. This may be a trait for pilots in 

general to overcome – barriers that we’re sitting here 

complaining about. Then again, that is the point of the 

process we’re going through today, isn’t it? To expose 

as many experiences as we have. I focus in more on 

the word “problem.” How often has it actually caused 

a situation I wasn’t able to resolve? It doesn’t mean 

the job was easier because of it. If you ask how often 

this has caused your job to become more difficult, 

9 Bowie VOR – UKW

10 Boeing 737 aircraft

11 Pre-Departure Clearance

12 Aircraft Communications Addressing and Reporting System is used for 

Datalink transmissions.
9 

I would certainly increase the frequency; places 

with more international arrivals tend to be better at 

English communication.

Rarely Explanation

Of the 12 pilots who reported “less than 10% of their 

interactions with controllers involved problems,” 33% 

provided comments. Presented below is a compilation 

of their experiences.

Communication or Equipment

Equipment malfunctions are very rare; and trying 

to understand what they’re saying sometimes comes 

up. Even 5% is likely to throw a negative impact on 

the outcome of the flight. If you take all my interactions with ATC, I have one or two problems in every 

flight. Quantified over all my flights, rarely are communication problems difficult to resolve.

Occasionally Explanation

Of the 25 pilots who reported “between 10-24% of 

their interactions with controllers involved problems,” 

40% provided comments. Presented below is a compilation of their experiences.

Communication Problems Depend Upon Country

When I experience communication problems, it’s 

the same reason – it breaks up the radio cadence – 

that’s the single, largest problem of all. It takes time, 

takes my concentration away from a lot of other tasks 

as I wonder when it will be my turn to speak. 

I go into San Juan every now and then, but it is not 

hard. We go to Mexico and Cancun and their English is okay. For the most part, English is very good 

in Costa Rica, Guatemala, and Panama. In Europe, 

everybody is raised speaking two or three different 

languages. What helps me out is learning to count 

in Spanish. When a controller gives numbers, I can 

translate them from Spanish into English.

Become Familiar and Go Total English

We understand that we’re an international airline 

now and 10 years ago, we didn’t understand that, 

even though we flew to all these areas. The Asian 

controllers are learning ICAO procedures, and as 

things become more predictable and better, problems should occur less. Just as Bangkok Ground is 

hard for us to understand, they have just as much 

difficulty understanding us – it’s occasionally hazardous. Sometimes it’s difficult for us to understand 

Scottish radios and accents. With three people in the 

cockpit and 30 minutes before we get to an airport, 

we’ll figure out what was said.

Frequently Explanation

Of the eight pilots who reported their interactions 

with controllers frequently involved problems, 38% 

provided comments. Presented below is a compilation 

of their experiences.

Regional Culture is a Factor

It depends on which region we go into. Pronunciation and accents can slow us down but we deal 

with it. If one or two of us have to ask, “What did he 

say?” that’s a good indicator. I always have problems 

in Saint Lucia or Curacao Control, but then I find 

Martinique not too bad when we talk to the tower 

controller. 

Often Explanation

Of the two respondents who reported 75-90% of 

their interactions with controllers involved problems, 

one offered the following comments.

Accent and Pronunciation Are Problems

The big problem is, if I don’t hear my call sign – especially the [first part of our company’s name] I have 

to have the entire transmission said again. Generally, if 

I miss it because of the accent, then the way numbers 

are said will confuse me and I will miss them also. 

Anything nonstandard invariably requires them to 

say it again. There are so many different words that 

can be put in any transmission – “knot,” “decimal,” 

or make a negative versus a positive clearance. 

Without Fail Explanation

One respondent reported more than 90% of his interactions with controllers involved problems. 

Table 4. Frequency of Communication Problems in Non-Native English-Speaking 

Airspace/Airports. 

Frequency of Communication 

Problems 

Number 

of Pilots Issues Discussed 

Rarely (Less than 10% of my interactions with 

controllers) 12 Communication or Equipment 

Occasionally (Between 10-24% of my 

interactions with controllers) 25 Communication Problems Depend Upon Country Become Familiar and Go Total English 

Frequently (Between 25-74% of my 

interactions with controllers) 8 Regional Culture Is a Factor 

Often (between 75-90% of my interactions with 

controllers) 2 Accent and Pronunciation Are Problems 

Without fail (more than 90% of my interactions 

with controllers) 1 Trouble Everywhere 
10 

Trouble Everywhere

Somewhere, there’s not a single flight that I don’t 

encounter some kind of problem. It may not be 

significant compared with others – but without fail, 

it happens.

35. Of the non-native English-speaking airports 

that you fly into, do you find the English language 

skills of other pilots and controllers comparable 

from one country to that of another? Please explain.

Among the 48 respondents, 31% indicated the English 

language skills of pilots and controllers are comparable 

from one country to that of another. Among the remaining 

pilots, 61% noted differences in English language skills 

among pilots and controllers in different countries/airports; two offered no comments and two were undecided.

Comparable Explanation

The pilots’ responses were organized into two general 

themes. The first involved speaking in their native or local language. The second related to an assessment of the 

English language proficiency of the pilots and controllers 

during a transaction.

Communication Practices

If I make position reports in Spanish, some South 

American controllers respond in Spanish. That’s when 

I have to fess up and say, “Okay, you just tested my 

Spanish vocabulary right there. You got all I got.” If a 

Spanish-speaking pilot speaks to a Spanish-speaking 

controller, and the controller responds in English 

because he just finished talking to us, they will keep 

their conversation in English. 

In Mexico, France, China, and Madrid, pilots and 

controllers speak to each other in their native languages.13 If I speak French to a French controller, it 

will stay that way for the duration of that conversation. Sometimes, when I hear [Aero Mexico pilots] 

in the U.S. – their English is quite good.

13 “In Annex 10, it is stipulated that radiotelephony communications shall be 

conducted either in the language of the station on the ground or in English, 

and that English shall be made available when pilots are unable to use the 

language of the station on the ground” (ICAO DOC9835, 2004).

English Language Proficiency

Most of the pilots and controllers speak English 

to get their points made. I’ve never felt in jeopardy 

because they didn’t speak English well enough. They 

think that we’re going to understand them and may 

take it for granted but it’s just not that easy.

Some countries have better English-speaking pilots 

than others; a lot are comparable between the pilots 

and the controllers. Some are excellent; however, we 

can have a problem with non-native English speakers in this country. So overall, they are somewhat 

equal; but it is very difficult for me to understand 

Piarco14 Control.

Not Comparable Explanation

According to the flight experiences of the other pilots, 

their written and oral comments indicated the English 

skills of the pilots and controllers in the areas they fly 

into were not comparable. Their responses were organized 

into nine general themes, listed alphabetically in Table 5.

Accent

For me, some controllers have thicker accents. We 

can have some non-native English-speaking controllers who are proficient in their job, with a thick accent and they get the information across to me very 

well. Another controller with the same thick accent 

who’s not as proficient – it’s going to deteriorate. 

I’ve had the most trouble and most workload trying 

to understand what ATC wanted us to do at Charles 

de Gaulle and Beijing. I find these to be the thickest 

and difficult accents to understand.

Busier Airports Have Better English Language 

Proficiency

Airfields with a higher frequency of international 

arrivals tend to have better English communication 

skills. If a field is primarily an international airport, 

the communication process evolved to a fairly effective level. The further away you get, at smaller or less 

developed airports, you notice less skill, especially 

among the small aircraft pilots. 

14 Piarco is located in Trinidad, West Indies.

Table 5. Pilot and Controller English Language Proficiency 

in Non-Native English Countries. 

Issues Discussed 

Accent 

Busier International Airports Have Better English Language Proficiency 

Culture 

Differences Reside Between Individuals Not Countries 

Limited English Language Skills 

Male vs. Female Voice 

Pre-Departure Clearance 

Pronunciation 

Ratings by Area 
11 

Culture

It varies from one country to another and culture is 

part of it – those with close ties to the U.S. or U.K. 

seem to have a better understanding of English. There 

is the perception [among some pilots] that some 

controllers in some countries make little attempt at 

communicating in English.

It’s been my experience that it is in the poor, less 

developed countries, where the language barrier 

is really there. It seems to me that many pilots are 

more comfortable communicating in their native 

language, and do so when afforded the opportunity. 

That concerns me, because I’m not following along 

in the conversation, and I need to.

When controllers become very proficient in English 

– controllers in San Jose, Costa Rica are very good 

examples – they go to the private sector because 

they can double their salary. Then, somebody new 

comes on who will start at the bottom and work up. 

I find countries like Germany, the Netherlands, 

and Israel versus countries that don’t teach English 

from the very beginning have an exceptional ability to communicate in English. There are countries, 

however – like Russia and China – where English 

is taught on a limited basis, if at all. So, it appears 

that a controller’s ability to communicate is limited 

to the job at hand.

Differences Reside Between Individuals Not Countries

I think the differences between the airports that I 

operate into are based more on the individual controller, not so much the country. I couldn’t pinpoint 

one country having a specific problem – obviously, 

mastery of the English language is the big difference. 

It’s the same with pilots – they vary a lot. Those 

from some countries have more problems. Pilots 

and controllers with English as a second language 

have a broader basis for the English language compared with the pilots and controllers where it is not 

as important. Controllers less familiar with English 

probably have limited exposure to it.

Limited English Language Skills

Controllers whose understanding of the English 

language is restricted to ATC terminology kind of 

freeze up when asked a question outside the box 

[ATC parlance]. Their communication is limited to 

basic ATC and to what they’re planning to give you. 

It’s the same with the pilots as the controllers.

One time at the Los Angeles Airport, a [foreign air 

carrier] in front of us had a locked brake. We could 

not get the point across to the pilot that he had a 

problem. He was very much ATC English. We called 

ATC and said, “The seven four in front of us has a 

locked brake; tell him, just don’t give him his clearance.” And that’s what happened.

Male vs. Female Voice

It’s easier for me to understand a deeper male voice 

than a female voice. I don’t know if it’s because the 

tones that are received through my headset are more 

readily ascertained because it’s a lower frequency 

or what.

Pre-Departure Clearance (PDC)

Everyone does the PDC different. PDC is a wonderful tool for speed and accuracy. When we’re trying 

to taxi an airplane and burning gas, trying to avoid 

other people, making sure we’re going to the right 

runway, taxiway, and trying to write down the clearances – by golly, something may go wrong. Throw in 

some weather, night, flight attendants calling us with 

a passenger problem, or toilet problem or whatever 

– it’s a recipe for a problem. We always try to get our 

clearance before we leave the gate, in some cases 

we get it when we taxi out. I’m finding that in a lot 

of places, if I ask for it before I taxi, sometimes they’ll 

give it to me, and sometimes they won’t.

Pronunciation 

I’ve found that Italian controllers tend to roll their 

“r’s” and Canadian controllers are easy to understand. 

Even though my mother is French, and I was raised 

speaking it, I find French controllers to have the 

strongest accents and sometimes will have trouble 

understanding them.

Ratings by Area

There is a huge difference depending where in the 

world you’re flying. English skills vary greatly by area, 

controller, and pilot. I find some pronunciation, inflection, dialects, and accents can be difficult for me to 

understand. I may have trouble with the phraseologies; and if I ask for a repeat, we can figure it out.

In the daytime, at the busier airports in some countries, the controllers will be more experienced and 

the quality of communication is much better. If we 

come in at night, we may get more junior controllers, and the quality can be significantly degraded. 

Another problem for us is controllers who switch 

back and forth from their native language – talking 

to their own guys – to English. It’s strange because 

we have to listen a little bit more carefully to hear 

our call sign.

Regardless of the areas the pilots flew through, to, 

and from, there were six generalities extracted from their 

comments and discussions. First, when busy, controllers 

don’t always have the time to say it right. Second, controllers can become frustrated with pilots who do not immediately grasp what is said in accented-English. Third, 

some controllers speak too fast for pilots to understand. 

Fourth, controllers who are more experienced make communicating easier. Fifth, as pilots are exposed to an area 

more frequently, communicating becomes easier. Sixth, 

accented-English requires increased attention.
12 

35a. Do you find that the intelligibility of some 

non-native English-speaking controllers causes you 

to work harder to understand them? (Think Montreal versus Katmandu or Johannesburg versus Dakar.) Use any other examples that you may care to.

In response to this question, 21% of the pilots answered with only the word “yes,” while another 54% 

offered comments indicating that, in their experience, 

there was a need to work harder to understand non-native 

English-speaking controllers. Some of the pilots named 

areas that were given in a context of “these increase the 

workload.” The areas are listed in Table 6.

Presented in Table 7 is an alphabetized list of the issues 

that increased their workload related to the intelligibility 

of non-native English-speaking controllers. One pilot 

reported no increase in workload. That pilot stated,

I didn’t find a big difference in non-native Englishspeaking controllers, and they didn’t actually cause 

me to work any harder to understand them. The 

controllers in Latin America, South America, and 

Europe are very good.

Accent

There is a different accent going from country to 

country or state to state; and that’s an issue when 

flying. We can go through five different accents and 

different countries. It is hard so we have to listen 

closely.

Areas Where Workload Increases

It is amazing how many of our pilots have trouble 

understanding the Scottish controllers, me included. 

I have to ask them a couple times where it is they 

want us to go because understanding what I perceive 

as heavy brogue over a bad radio makes it tough. 

Rome is very difficult for me too. In some ways, it is 

because I have a problem with the controller’s pronunciation and enunciation. Lima, Peru is difficult, 

and sometimes Venezuela’s clearances are extremely 

difficult to ascertain. In the Caribbean, Cuba’s almost 

like talking to Miami Center. They’re just outstanding 

– very polite and courteous, professional. Jamaica 

can have problems sometimes, but typically, they’re 

very good, and their radios are very good.

English Proficiency Varies From Country/Controller to 

Country/Controller

There is a wide skill level of English spoken from 

country to country, and even from individual to 

individual. One day we get controllers who are 

excellent, and the next day we’ll get some who are 

Table 6. Areas Where Pilots Say the Intelligibility of Some Non-Native EnglishSpeaking Controllers Causes Them to Work Harder to Understand Them. 

Areas Where Intelligibility Affects How Hard Pilots Work to Understand 

Bogota and Paris 

Egyptian controllers are difficult compared to German 

Germany is easy compared with France 

Havana is better than Miami 

Haiti and Dominican Republic are difficult 

Martinique is inconsistent – very good to poor 

Mexico is not bad; Mexico City is better than Costa Rica 

Montreal is not usually an issue; Montreal is more difficult than Charles de Gaulle or London Heathrow 

Moscow is more difficult than Mexico, Paris, or Stockholm 

Mumbai is more difficult than Stockholm 

Panama is better than Curitiba (Brazil); Panama is slightly better than Ecuador 

Piarco Control (Eastern Caribbean) and St. Lucia are always hard; St. Lucia is always terrible 

Scottish controllers and sometimes Irish controllers are difficult 

“Stans,” Uzbekistan, Pakistan, etc.; all the “Stans” on to India; Eastern Siberia 

Tokyo is better than Korea 

Venezuela 

Table 7. Issues Affecting How Hard Pilots Work at 

Understanding Non-Native English-Speaking Controllers. 

Issues 

Accent 

Areas Where Workload Increases 

English Proficiency Varies From Country/Controller to Country/Controller 

High Pitched Voice 

Poor Radio Equipment 

Pronunciation 

Repeats 

Speech Rate 

Varying Cultures 
13 

not quite as good. Some areas are excellent, while 

others are difficult. We have to work harder with 

non-native English-speakers. 

Mexico is pretty good unless we just happen to get 

a controller who’s not as proficient. Peru is perceived 

to be the most difficult due to poor radio quality and 

limited English language proficiency. Pilot stress level 

is very high passing through the “Stans” on the way 

to India – Uzbekistan, Turkmenistan, etc. – because 

of limited English skills.

Some Russian controlled airspace – East Siberia and 

Mongolia – is still an issue. In Eastern Russia, English 

isn’t a problem, as many controllers are furloughed 

Aeroflot pilots; however, most are being recalled to 

work. We have been turned back from the border 

of Russia several times in the past year because they 

didn’t have an English-speaking controller on duty.

High Pitched Voice

I have great difficulty understanding female Japanese 

controllers’ voices. There is a very definite difference 

in its pitch. I don’t have the same difficulty with male 

Japanese controllers’ voices; it’s as if we’re in Chicago. 

I can hear and understand very well. 

Poor Radio Equipment

When flying the “Poles,” we go from Magadan15

Control to various air traffic control agencies in 

Siberia, and the area below Siberia. My experience 

has been that Russian controllers have very poor 

equipment. And I find controllers in Mongolia are 

very, very difficult to understand; and the quality of 

their equipment is very, very poor.

I find Central America really good because there is 

basically one facility for all of Central America. The 

radios are very good – Panama is real good. 

When I fly to South America, my experience has 

been that both Venezuela and Colombia are fair; 

Ecuador is poor; it seems the farther south we go, 

the more difficult it gets. To me, Peru is the most difficult, for two reasons – bad equipment coupled with 

a limited understanding of the English language.16

Amazonia also has very poor equipment. There are 

a lot of mountains to deal with and hundreds of 

miles between the transmitters. It seems to me that 

it would be easier if they could bounce the signal 

off a satellite than do point-to-point transmissions.

Pronunciation

It’s not just a question of the quality of the equipment; I have trouble with the way waypoints and 

fixes are spoken – they never sound like they do in 

English. I may have looked at the fixes on the chart 

in advance; and after I’ve heard them three times, I 

figure out what fix it is.

15 Magadan is located in Northeastern Siberia.

16 The pilot may be referring to English skills beyond those used in ATC 

radiotelephony.

Repeats

The controller workload increases with all the repeats and airplanes they talk to. But, it varies by controller, and the enroute controllers are most difficult 

because they’re generally in more remote locations. 

If we don’t understand or have a misunderstanding, 

I have to say, “Repeat,” “Say again,” or “What do 

you mean by this?” This increases the workload for 

pilots and controllers. It is best not to use the builtin speakers in the cockpit. Wear a headset, put in 

an earpiece, and try to hear it clearly the first time 

rather than having to ask for clarification.

Speech Rate

It’s been my experience that there are quite a few 

controllers who speak too rapidly and with heavy 

accents, causing other non-native aircraft to request 

repeated transmissions. I’ve found this to be particularly true when they are using poor radio equipment. 

A request for repeat will only cause some controllers to speed up. That in turn causes congestion on 

the frequency. Controllers who seem to speak at a 

normal speed do not have much of a problem with 

us asking for repeats. 

Varying Cultures 

The more unintelligible I find someone is, whether 

non-native or native English – the harder I work. In 

some Asian countries, approach controllers don’t 

seem to be confident in their English-speaking ability. It may be that they are relatively new to English 

and commercial air traffic control. My two Beijing 

trips and Magadan were challenging. I found South 

America enroute very difficult; however, Sao Paulo 

and Buenos Aries approach, tower, and then departure controllers were quite easy to work with. They 

stayed on the page and used standard terminology. 

Sometimes it is very difficult for me to understand 

Scottish and Irish controllers, which is strange since 

they are part of the U.K.

35b. What makes some non-native English-speaking controllers’ speech more difficult than others to 

understand? (e.g., speech rate, pronunciation)

The responses of the pilots were organized into four 

broad themes: (1) Voice Properties (Accent, Dialect, Pitch, 

Proficiency, and Pronunciation), (2) Delivery Technique 

(Cadence, Speech Rate), (3) Radio Equipment (Broadcast 

Sound Quality, Spotty Radio Coverage), and (4) Unpublished Radio Frequencies. The respondents reported these 

factors influenced the understandability of non-native 

English-speaking controllers. One interviewer also asked 

a group of controllers several follow-on questions, and 

their responses appear at the end of question 35b.

The ability to understand a speaker is also affected by 

hearing loss. Some of the symptoms of age-related hearing 

loss include: (1) Difficulty understanding spoken words, 

speech sounds mumbled or slurred, (2) High-pitched 

sounds are hard to distinguish, (3) Conversations are 
14 

difficult to understand, particularly when there’s background noise, and (4) Men’s voices are easier to hear than 

women’s voices, primarily because men’s voices are lowerpitched. Thus, the pilots’ responses are likely to reflect both 

personal as well as environmental factors in combination 

with the four broad themes mentioned above. 

Voice Properties

Accent

It is hard to break this out and say, “This country 

is necessarily better than this other one.” It depends 

on the controller. I’ll be doing great; and then get a 

handoff to somebody else in the same airspace, and 

it’s like – “Can I go back to the other one, please?” 

We know the accent, dialect, pronunciation, rate, as 

well as the ability to enunciate vary from controller 

to controller. Enunciation is a problem – it doesn’t 

matter what country we’re in – if controllers enunciate differently than we expect, transmissions sound 

garbled. 

Dialect

If the big picture here is – we’re all going to speak 

English together – it’s hard to expect anyone to lose 

their accent. Even in the U.S., we’ve got different 

accents; there are people we’re all going to find 

hard to understand. They’re speaking the same language, theoretically; if you slow it down – I think 

that’s the key.

It depends on the region – each region’s different; 

each country’s going to be a little different. They have 

the basics, and that’s as far as it goes. When there’s a 

breakdown, communication comes to a stop. Then 

we’re on our own and we’re going to do what we 

have to do, what we think is right.

Pitch

What makes a controller’s speech difficult for me to 

understand? (1) Pitch of voice; (2) Pronunciation and 

slurring of the words – I would tie those two together, 

pronunciation/slurring words; (3) Nonstandard verbiage; and (4) Quality of equipment. 

Along with [pitch] is the lack of variation or modulation. There is no up and down – everything sounds 

the same to me. If I miss one word, the rest of the 

words seem like one gigantic word to me. I can’t 

figure out where the words break apart. It seems to 

me that we’ll ask for repeats from female controllers 

much more frequently than from a deeper, monotone 

male voice. Actually, it may have nothing to do with 

it being women; it’s the way the radios carry their 

voices.17

Proficiency

In Curacao, we have a [note] on our flight plan that 

says Curacao is in training. All controllers are in training down there; so anytime we go through Curacao, 

17 It may be the higher pitch, when coupled with aircraft and communication 

equipment noise, renders female voices less intelligible than lower-pitched voices.

we’re talking to a trainee. We can always hear the 

[instructor] in the background, either correcting or 

suggesting things to him; so again, sometimes as a 

training issue, sometimes a lack of effort. The further 

south we go, I find a tendency among controllers to 

be less proficient in English.

Pronunciation

Pronunciation that includes the syllable emphasis 

and enunciation affect understanding. It seems to 

me that some controllers just become lazy in their 

pronunciation that I find difficult to understand. If I 

say, “Say again,” the quality of their English improves 

when they realize that I didn’t understand what they 

said. The other thing I experience is the tonal quality 

of some of the controllers. If you heard them, you 

would know what I’m talking about, – they start to 

use slang, instead of saying, “Roger,”18 it is “Raja.” 

Also, if they’re using something I’m expecting in ICAO 

terminology, I can probably understand; however, 

if they use something other than that – or a local 

procedure that is not really written out – it becomes 

difficult for me.

Sometimes, it’s difficult for me to understand Japanese pronunciations because I’m not used to it. It’s the 

inflection, enunciation, and pronunciation of words 

and letters. The Japanese controllers have a practice 

of putting an “O” in all the call signs “[company 

name] O eight eight nine,” versus “[company name] 

eight eight nine.”

Delivery Technique

Cadence

I have a problem with the speed and cadence. 

They may place the wrong emphasis on the wrong 

syllable. If he doesn’t say “[call sign] we’ve got your 

clearance when you’re ready to copy” – we’re not 

prepared for it; and it may be a complex clearance. 

Speech Rate

When you add pronunciation, cadence, and accent, speaking too fast is the biggest problem we 

have. Some controllers seem to speak fast to mask 

their fluency while others speak rapidly because they 

think they’re pretty good at English. But, they’re not 

as good as they think because we miss what they 

say or don’t comprehend it. 

We also have more difficulty understanding when 

they are in a hurry because there’s a lot of traffic out 

there. When the controller is rapid-fire machinegunning these clearances out, sometimes, if we have 

a question, it’s very difficult to get a word in there. 

We’re no longer listening because we’re still trying 

to process what was said, remembering what was 

heard, and deciphering or interpreting the language. 

And I feel that controllers dealing with a high volume 

of international flights, need to understand that 

18 A standard air traffic term used to indicate, “I received your message and 

understand it.”
15 

slowing down the rate, and even just separating the 

call sign from the body of the communication being 

given, could make the difference. It seems to be a lot 

better when non-native English-speaking controllers 

are slow and deliberate, then I can understand them 

the first time; it is easier. So that’s the single greatest 

thing – a controller speaks too fast to everybody and 

this leads to too many repeats. 

Radio Equipment

Broadcast Sound Quality

Which is better, the equipment, or speech production? I think we could probably understand the 

verbiage if the equipment was good enough to hear 

[what was spoken]. If it’s clear, no static, and not 

distorted and scratchy, we can work around it as 

long as we can hear and understand it. I experience 

reverberation every once in a while. It’s different from 

a barrel sound – it’s a tunnel effect, I hear an echo. 

I think it is a problem in the relay between station 

to station before it spits it out to us. 

And the other one – we call it a “tin can effect.” 

That’s when it sounds like I’m talking into a tin can 

with a string line attached. I find that it happens when 

I’m flying into Lima, passing through Ecuador, and in 

a descent, we switch to a VHF frequency – however, 

it sounds like the person is speaking at the bottom 

of a 55-gallon drum. There are echoes, there are 

delays in the transmission, where we’re letting them 

know we’re there.

Spotty Radio Coverage

Kingston sometimes uses the south frequency for 

the north, and north frequency for the south. Panama 

recently added a new sector – now there is North 

and South Panama. We used to get five minutes 

of dead time or so, especially if the weather was 

bad. Now when the weather is good, we can talk 

to them within a minute or two. We can contact 

them using VHF, make a relay, a phone patch, wait 

five minutes, or go to HF;19 but, by the time we 

tune it and make a call, the VHF will probably be 

coming back in.

There are two parts to Lima – Lima North and Lima 

South. There is a stretch where we’re out of contact. 

They have a common HF frequency – 8 8 5 5; and 

we’re told that if we can’t reach them to call on 8 8 

5 5. I tried to do that, and I’m here to tell you none 

of us have gotten hold of any controlling agency on 

HF. HF coverage is nonexistent there.

There is one way we get around communication 

problems – we listen to American, Continental, 

United, and Delta; and relay information for each 

other. We have 300 miles of airplanes and we can 

talk to each other; and we do relay clearances and 

requests all the time down there. 

19 High Frequency

Unpublished Radio Frequencies

There are frequencies that are never available – 

either the agencies did not put the right information 

on Jeppesen charts, or Jeppesen did not put it in the 

communication boxes on their charts. I have examples 

in my best practice guide of 20 frequencies – and 

there’s not a single one of them on a typical chart. 

Follow-on Questions 

One of the interviewers asked the pilots several followon questions to their discussion about proficiency. The 

first question addressed concerns with communications 

that deviate from the expected pattern of information 

exchange between pilots and controllers. The second 

dealt with the pronunciation of numbers by controllers.

Outcome of Unscripted ATC/Flight Deck 

Communications

In response to the question, “If ATC gave you a 

clearance and you said, Unable, and you came up with 

an alternative, would they understand?” the following 

dialogue occurred: 

I have experienced silence on the air. They may be 

talking to a supervisor, or trying to find out, “Now 

what do we do? This crew is not accepting what I 

just gave them; I don’t know what to give them now.” 

So we’re on our own.

Interviewer - Do you get to stay at that altitude until 

they come back?

Yes, unless it was a dangerous situation.

Interviewer - Then you let the controller know that 

you’re going to descend or climb?

We’ll just tell them. We don’t even ask in some 

places. “We are deviating for weather, we are doing 

this.” We’re telling them; and they’re going to have 

to make it work for us; otherwise, we would have 

gone through a thunderstorm.

Pronunciation of Numbers

In response to the interviewer saying, “With all of 

your different language experiences in other countries, 

imagine hearing controllers speaking the numbers one 

through ten,” the following reply was offered by the pilots:

For me, the Europeans do the numbers the best, 

and China and Taiwan the most difficult. The others 

are in between. And again, with South America, I 

haven’t really had any trouble with numbers. The 

Japanese tend to insert “O’s” when saying numbers.

36. When flying in a non-native Englishspeaking country, how often do controllers 

use ICAO standard phraseologies for routine 

communications to speak to you? 
16 

As shown in Table 8, 85% of the respondents reported 

at least 75% or more of their interactions with controllers 

included the use of ICAO standard phraseology during 

routine communications when flying in a non-native 

English-speaking country. Furthermore, an additional 

12% reported they frequently heard controllers use ICAO 

standard phraseology when communicating with them. 

However, one pilot reported when flying in a non-native 

English-speaking country, controllers occasionally used 

it for routine communications when speaking to them. 

None of the pilots said they occasionally heard controllers 

use ICAO standard phraseology during their communications with ATC.

Only 25% of the pilots who selected “Without fail,” 

“Often,” and “Occasionally” made comments. Their 

comments from the written and interview portions of 

the questionnaire were organized according to thematic 

content and response selection. 

Without Fail Explanation

Among the pilots who selected this option, 31% 

provided comments. 

Non-Native Speakers Know Only Standard Phrases

Generally, we hear ICAO phraseology. When it 

strays, it’s difficult to understand – however, it doesn’t 

happen very often.

Often Explanation

Of the 28 pilots who selected this option, only 21% 

commented.

United States Nonstandard and Unusual Events 

Everywhere

The non-native English-speaking [countries] use 

more ICAO standards, certainly more than we do in 

the U.S. – that is in regards to terminology. 20 It’s the 

phraseology they are trained with, and that’s what 

they tend to give us. It doesn’t seem like there’s a 

whole lot of nonstandard ICAO words. Sometimes 

the words they give us, and how fast they say them, 

may cause me to [ask for a] repeat. They seem to go 

out of their way to use standard phraseology. Most 

controllers are toward the high end; I would say 

more than 90% are very professional and very good 

at what they do. 

My concern is when we come into the nonstandard arena, when there’s something wrong with the 

20 Terminology and phraseology used interchangeably

aircraft and we have to convey a lot of information 

at a given time and we need very quick – not resolutions – good information right now – is it readily 

available and how would it be conveyed, standard 

phraseology or nonstandard?

Frequently Explanation

Of the six respondents, two commented.

South America Is Nonstandard and Lacks 

a Pattern of Communication

When we go to South America, there can be a lot 

of nonstandard communication. I have experienced 

the terminology to be quite a bit different – not “line 

up and wait,” but “you’re not cleared to land.” The 

“continue”– we hear that a lot. When I call approach ATC will say, “Continue;” and if I ask about 

the weather, I don’t think they understand what I’m 

talking about because of their limited [non-ICAO] 

English. They know a couple of phrases and that’s 

about it. If we ask them any other questions, or query 

something, we get into the nonstandard because they 

don’t have a set way of doing things – very limiting. 

They try to be more ICAO-standard than what we 

think. We’re used to what we do here, except we’re 

not necessarily ICAO standard. If you ask a group 

of Brazilian pilots what they think of coming to the 

U.S. and how standard we are, you might find they 

think we are very nonstandard.

37. When flying in a non-native English-speaking country, how often do controllers use Common English for routine communications to 

speak to you? 

Common or plain English occurs when either the 

pilot or controller switches from standard phraseology 

and speaks in a conversational manner. Table 9 shows 

that only 25% of the respondents reported controllers 

frequently (or greater) use Common English for routine 

communications when flying in a non-native Englishspeaking country. Notably, 44% indicated they occasionally hear Common English during their interactions, and 

an additional 31% said their interactions with controllers 

rarely involved Common English. 

Without Fail Explanation

Of the two respondents who reported more than 90% 

of their interactions with controllers involved some use 

of Common English, one offered an explanation.

Table 8. Frequency of ICAO Standard Phraseology Usage by Controllers in NonNative English-Speaking Countries. 

Frequency of ICAO Phraseology Usage Number of Pilots 

Without fail (more than 90% of my interactions with controllers) 13 

Often (between 75-90% of my interactions with controllers) 28 

Frequently (between 25-74% of my interactions with controllers) 6 

Occasionally (between 10-24% of my interactions with controllers) 1 

Rarely (less than 10% of my interactions with controllers) 0 
17 

When things go badly, controllers use Common 

English to fix it. They’ll say, “[Company name] we 

wanted you to go here, now go there.”21 I consider 

Common English to be what the controllers use when 

they are trying to explain what the clearance was. 

They’re trying to resolve it and will use Common 

English to fix it.

Often Explanation

Six of the eight respondents who selected between 

75-90% of my interactions with controllers provided 

comments during the interview. None included a specific 

example during their discussions.

Controllers do talk to us after they give us the clearance; they’ll come back and talk to us in a clarification 

sense and use Common English. Most controllers 

are pretty professional with what they convey in 

the clearances – climb to and maintain a particular 

altitude, or descend to maintain a certain altitude. 

It’s been my experience that in Mexico, controllers do a good job. They use their best English. Most 

controllers get what they want with routine communications; if not, they attempt to use nonstandard 

terms. But then again, it depends on their fluency; 

if they’re not confident of their English, they tend to 

avoid Common English completely. As their confidence level builds, they try to use it occasionally 

and to varying degrees of success. The exception is, 

when they communicate in their native language to 

a crew of their region. 

Frequently Explanation

Of the two respondents, one offered the following 

comment.

Typically, controllers use ICAO standard phraseology. Occasionally they’ll say something in Common 

English. ICAO is what I expect and what I get. ICAO 

standard phrases are easier for me to understand and 

Common English can be used to verify.

Occasionally Explanation

Twenty-one respondents circled “Occasionally (between 10-24% of my interactions with controllers).” 

The discussions by 48% of the pilots were organized 

into two overlapping themes: The degree with which 

Common English occurs depends on (1) how com21 This is Common English used in lieu of “[Call sign] cleared to CDG via 

Aries arrival.” Throughout the interviews, pilots used Common English in 

lieu of giving specific clearances.

fortable they are with their command of the English 

language and (2) how structured the ATC environment 

is to support its use by controllers.

May Practice English to Gain Proficiency

My experience has been that it depends on the part 

of the world I am in as to what I will hear. Generally, 

some controllers are good, and some are fair in Common English. If they are comfortable with Common 

English, they may say a few words. Sometimes when 

there’s time, they’ll want to talk to us using Common 

English for practice. However, ICAO phraseology is 

mostly used and Common English may be used to 

explain ICAO phraseology. It may not be what we’re 

expecting, or what we’re used to hearing, but we get 

a drift of what they want us to do – that probably 

comes from experience. 

When the other controllers try to speak English, 

we often can’t understand them; they shy away from 

trying to speak it; they don’t want to be embarrassed. 

So they stick to the ICAO phraseology.

Structure of Phrases Varies with Country

For me anyways, it seems like the more structured 

the environment the more ICAO terminology is used. 

When I’m in the NATs,22 it’s 100%; in the U.K, it’s 

about 100% – they’ll throw in some of the common 

language like, “Yeah,” “Roger,” or something like 

that; and in Mexico and South America, it’s mostly 

ICAO phraseology. 

Experienced pilots know about weather and what 

to expect because there’s a lot of repetition in our 

flights. I would hate to throw new pilots into that briar 

patch, so to speak; because there could be misunderstandings. This is true for our ground control and 

push back crews – they have been told what we’re 

supposed to say, and if we say it a little different – like 

“I am setting the brake” instead of “parking brake 

set”– we sometimes get a pause; they’re not used to 

that; they’re used to the routines. 

Common English might be used when coordinating 

a ground delay or taxi back to the gate, maybe the 

routing is nonstandard, or ATC is trying to figure out 

why we need to delay. Some experienced controllers 

revert to Common English to help us understand an 

instruction like taxi to holding point. If we ask for a 

repeat, they may use Common English so we can 

understand it by saying, “Do not enter runway.” Of 

22 North Atlantic Tracks

Table 9. Frequency of Common English Usage by Controllers in Non-Native EnglishSpeaking Countries. 

Frequency of Common Language Usage

Number of 

Pilots

Without fail (more than 90% of my interactions with controllers) 2 

Often (between 75-90% of my interactions with controllers) 8 

Frequently (between 25-74% of my interactions with controllers) 2 

Occasionally (between 10-24% of my interactions with controllers) 21 

Rarely (less than 10% of my interactions with controllers) 15 
18 

course, when we ask for clarification or progressive 

instructions, they may break it down into one or two 

words at a time for both themselves and the pilot. 

In the cockpit, standard phraseology works the best 

for all of us. They understand what we’re saying; we 

understand what they’re saying. 

Rarely Explanation

Fifteen respondents reported that non-native Englishspeaking controllers used Common English during their 

interactions. Of these pilots, 73% commented on their 

interactions. Once again, there were two overlapping 

themes: The degree with which Common English occurs depends on (1) how comfortable they are with their 

command of the English language and (2) how structured 

the ATC environment is to support its use by controllers.

Non-Native English Speakers May Not Be 

Uncomfortable Speaking English

I’ve rarely experienced any familiar conversational 

English. It just doesn’t happen because I think they 

are trained to be proficient in ICAO standards and 

that’s their safety net. They keep trying to go back to 

the standard phraseology; and when they can’t they 

finally say, “Hey [Company name] what are you doing?” or “We want you to turn here now – go there.” 

It seems to be their last resort.

When we’ve spoken with particular non-native 

English-speaking controllers long enough and they 

feel very comfortable with us, they may practice their 

Common English but it just doesn’t come out right. 

Their English is not good enough yet. If less proficient 

controllers start using nonstandard [phraseology] and 

a heavy accent is added, with poor pronunciation – 

we will have a problem understanding them. If we’re 

trying to set up a 10-minute hold, get the cabin ready 

for descent; then confusion can drastically escalate.

Varies with Country

When dealing with non-native pilots, the nonnative English-speaking controllers seem to attempt 

standard phraseology. The order of the words might 

be different; for example, in the U.S., ATC might 

ask, “[Call sign] give me your Kagis23 estimate?” The 

Japanese controller won’t say it that way. He’ll say, 

“Estimate at Kagis.” The first time [you hear it] or if 

you didn’t anticipate the request, you might say it’s 

not how we would hear it domestically. 

It’s been my experience that non-native English-speaking 

controllers are not that comfortable with English; they 

lack knowledge of the language to issue it any other way. 

The exceptions are that the controllers in Germany, the 

Netherlands, and some Scandinavian countries are very 

familiar with English as a second language. They can 

use slang and Common English to get their point across. 

Mexican controllers routinely use Common English; 

Europeans rarely do. In Central and South America, it 

could lead to confusing directions, instructions.

23Kagis is a fix in Japan and is used here for illustrative purposes only.

38. When flying in a non-native English-speaking 

country, how would you describe the controller’s 

ability to communicate with you in Common 

English? 

This is a multifaceted question that explores how well 

pilots understand non-native English-speaking controllers when they use ICAO phraseology and when they 

deviate away from it. These controllers may believe they 

are proficient in their knowledge and use of the English 

language to the point where they may speak to pilots in 

Common English, jargon, or slang. Pilots may experience problems that are language-based with potentially 

adverse consequences. By asking very specific questions, we 

probe into their experiences during these flight situations. 

Each question (and corresponding probes) appears with 

its specific results and discussion as stand-alone items. 

As shown in Table 10, 17 of the pilots describe the 

controllers’ ability to communicate in Common English 

as good, while another 20 reported it as fair. Only 7 

described it as poor. No one described communication 

as terrible. One respondent did not make a selection 

although his written comments and discussion during 

the interview included “excellent,” “good,” and “poor.” 

Also, two respondents circled multiple selections; while 

their comments on the written portion and during the 

interview included “good,” “fair,” and “poor” for one 

respondent, and “good” and “poor” for the other. Only 

one respondent circled “Their communication skills 

are excellent.” Unfortunately, it was voided because he 

evaluated the Common English of British controllers.

Good Communication Skills Explanation

Approximately 71% of the pilots who said the Common English communication skills were good offered 

explanations. The controllers’ ability to communicate 

with them in Common English depended on the language 

production skills (accent, pronunciation, and speech rate) 

of the controllers, coupled with the pilot’s attention and 

prior experience flying in that particular country. 

Attention and Experience Are Needed for 

Understanding

I find the most troubling parts involve frequency 

changes, altitudes, and clearances. A lot of times, 

we hear attitudes in their tone of voice and patience 

level, especially if we ask them to repeat something. 

It’s so busy, in many parts of the world, it’s hard to 

get back in and say, “Say again,” let alone [ask a 

second or] third time. 

The first time we go into someplace where we can’t 

understand the words, we work harder. The more 

we’re there, the better we understand their English. 

Once we’ve been there and know what to expect, a 

clearance out of the blue can be understood. If ATC 

says “[Company name] so and so you’re cleared to 

X,” I’ll say “[Company name] so and so cleared to 

X,” and make sure they agree we’re cleared to X.
19 

Depends on the Country

Controllers who use normal English phraseology 

are good. And the ones who don’t know English will 

not talk to us. Either way, the Common English that 

is used is good enough that we can figure out what 

they are trying to get at.

It’s been my experience that European controllers, especially the German controllers converse 

well. We’re relatively new flying over to Delhi; we 

have a little difficulty in Pakistan, Afghanistan, and 

Kazakhstan because they are as new for us as we 

are new to them. So far, I’ve experienced very little 

Common English in the Middle East; however, usually we understand. I flew to the South Pacific going 

through Tonga, and some of those areas were difficult 

for me. And all through Micronesia24 – there are some 

difficulties there – and some in Russia; and much 

more in China. The communication skills among 

Japanese controllers are good because we communicate with standard phraseology and it works. 

If we had to explain a complex problem in a South 

American country, I don’t think the message would 

get through. As a general rule, the farther south you 

go, the more difficult it gets. 

Language Production (Accent, Pronunciation, 

Speech Rate)

For me, the root of the problem is accents, not air 

traffic control English. Most of the controllers I’ve 

run into are fairly good, and it’s their pronunciation 

or inflection that may be a little bit different. The 

more experience we have in that country the better 

we can understand their pronunciation. When they 

talk too fast, it’s hard for us to understand.

Only Fair Communication Skills Explanation

Approximately 70% of the pilots who said the Common English communication skills were only fair provided 

commentary. The controllers’ ability to communicate with 

them in Common English depended on the language 

production skills (accent, pronunciation, and speech rate) 

24 Micronesia is located in the western Pacific Ocean about 2,500 southwest 

of Hawaii.

of the controllers, coupled with the pilot’s attention and 

prior experience flying in that particular country. 

Common English Is Limited or Not 

Attempted by Pilots

It is hard for me to ascertain how good non-native 

controllers’ English skills are because I make no attempt to use Common English with them. As a second 

language, it’s fair, but that’s only the few words that 

might be used about a flight. If the flight is normal, 

there is no need to make a transmission outside of 

ICAO standard phraseology. 

It’s a lot harder to communicate when we want to 

do something out of the ordinary because of weather 

or something else. In the U.S., I can ask a controller, “Do you have any smooth rides?” or “Are the 

rides any better above us or below us?” If we are in 

another country, I say I want to go up or go down. I 

don’t try to push their limits.

It’s Open to Interpretation

When we fly in a non-native English-speaking 

country, we hear so many words that seem to have a 

different meaning. When a controller starts speaking 

English outside of what we’re expecting, my interpretation and his interpretation may be different. It’s 

the same as a non-native pilot trying to speak to a 

controller in the local language. If it is terrible, he’ll 

want the pilot to come back to the ICAO standard.

Lack of Proficiency Forces Structured ICAO Phrases

I find that when we step outside the bounds of 

ATC English, it becomes more difficult for them to 

express what they want to say and more difficult 

for us to understand what they’re trying to say in 

Common English. Basically, if ground crews want to 

hear, “Parking brake set,” even the phrase, “parking 

brake is set” is outside of the norm. Common English 

is usually involved in these kinds of nonstandard 

situations; asking a controller for a “ride report” or 

something else is out of the ordinary. 

Table 10. Controller Common English Skills in Non-Native English-Speaking Countries. 

Common English Skills 

Number 

of Pilots Issues 

Their communication skills are good 17 

Attention and Experience Are Needed for Understanding 

Depends on the Country 

Language Production (Accent, Pronunciation, Speech Rate) 

Their communication skills are only fair 20 

Common English Is Limited or Not Attempted by Pilots 

Level of Ability Depends on Interactions With EnglishSpeaking Pilots 

Their communication skills are poor 7 English Proficiency 

English Ability Is Theater-Specific 

Their communication skills are terrible 0 

Invalid – Rated British Controllers 1 

No selection circled 1 

Multiple selections circled 2 
20 

If the controller’s communication skills are only 

fair, his ability to understand and respond is limited. 

A worst-case scenario is a situation where the pilot 

wants to tell the controller they have hot brakes, or 

a gear fire. These types of transmissions don’t go 

through very well. Two or three repeats may not be 

enough; a taxi to the gate may be all the controller 

understands. I don’t want to taxi to the gate, I want 

to know if he sees a fire.

Level of Ability Depends on Interactions With 

English-Speaking Pilots

It’s been my experience that the level of ability is 

dependent completely on the volume of Englishspeaking traffic through that sector. If everything is 

going as planned, Chinese and Japanese controllers 

do a pretty good job; however, if there is a malfunction or emergency, all bets are off.

If I was asked the question – Where would I prefer 

to deal with an emergency, the Atlantic or Pacific 

area? – I’d be much more comfortable having a problem in Europe than in China, Japan or in the Asian 

Pacific. Canada and Europe are the best. Germany 

is excellent. So the answer to the question depends 

on where you are. 

Poor Communication Skills Explanation

All of the pilots who provided comments described 

the controllers' Common English as poor.

English Proficiency Poor25

Some countries and individual controllers are 

terrible at Common English, and we have no flexibility [outside of ICAO standard]. Any nonstandard 

requests are often difficult to communicate. Although 

their ATC English is good, some do poorly if they try 

Common English.

25Throughout the interviews, pilots had difficulty separating Common English 

and standard phraseology in English.

English Ability Is Theater-Specific

As a pilot, you could probably get away with telling someone working Havana Center that you had 

white caps in your coffee cup and what the ride is 

like; I don’t think you ought to try that in China. In 

Central America, you have a problem when you get 

off standard phraseology. Panama is good. In between 

them you just have Kingston and [the controllers are] 

Jamaican, so it’s not bad.

From that point south, it is really difficult. I’ve found 

that if I ask about sports events like the World Cup it 

goes nowhere. Any nonstandard request or remark 

is very difficult to communicate. If we’re not using 

standard phraseology or it’s not the expected communication at that point of the flight, it’s difficult to 

catch it in the first communication. In Europe, they 

understand Common English more than in South 

American.

38a. In general, how much attention is required 

for you to understand what a non-native Englishspeaking controller is saying in English? 

The pilots’ responses and compiled comments from the 

written and interview portions of the questionnaire are 

included below. As shown in Table 11, 65% of the pilots 

reported either a considerable (42%) or a great (23%) 

amount of their attention was required to understand the 

English spoken by non-native speakers. No one thought 

understanding these controllers was effortless. 

A Great Amount Explanation

Eleven respondents circled “A great amount.” One 

respondent made no comments. Among this group of 

pilots, 91% made comments that were organized into four 

issues: Pilot Experience, Area of Operation, Deliberate 

Listening, and Crew Resource Management.

Depends Upon Pilot Experience

How much attention is required is probably determined by what experience the pilots have in that 

Table 11. Amount of Attention Required Understanding Non-Native English-Speaking 

Controllers. 

Amount of Attention Required 

Number 

of Pilots Issues 

A great amount 11 

Depends Upon Pilot Experience 

English Ability Is Theater-Specific 

Requires Deliberate Listening 

Requires Extra Crew Resource Management 

A considerable amount 20 

Nonroutine Situations Are Problematic 

Requires Deliberate Listening 

Requires Extra Crew Resource Management 

There Is A Learning Curve 

Understand Can Be Lost in Translation 

A moderate amount 13 

ICAO Phraseology Makes Understanding Easier 

Pilot Fatigue Exacerbates Attention 

There Is a Learning Curve 

A limited amount 4 English Ability Is Theater-Specific 

It is effortless 0 
21 

theater. It’s almost like [flying as] a single pilot sometimes when you have someone who is new in a new 

area – you cannot assume that pilot understands – so 

the workload is definitely higher.

At [company name], a pilot’s first flight over there 

is as a listener. They don’t do the speaking on the 

radio. They are flying the plane, manipulating the 

controls and listening. 

English Ability Is Theater-Specific

The amount of attention to communication has an 

affect on situational awareness. Frequently we say to 

each other, “What did he say?” “Did you get that?” 

We are always on our toes. Before I even squeeze the 

trigger to communicate, I try to figure out what they 

are going to say back to me. It takes a great deal of 

time and attention in a non-English-speaking country. 

InMexico, communication is very attention-intensive 

– we have to make sure everybody understands, 

especially if there is a problem.

Requires Deliberate Listening

Benefit of Wearing a Headset

I am considering getting a noise-cancelling headset 

so both my ears can listen in a quiet environment 

because of the distortion coming out of the speakers. I know that one ear is better than the other is at 

some frequencies.26

Deliberate listening is required when flying in a 

non-native English environment! It focuses a lot of 

my attention because I want to be absolutely sure 

about what is being conveyed. I listen much more 

intently than I would in the U.S., only because I 

tend to discern the meaning here much more easily. 

Workload Increases in Non-normal Situations

I listen intently and I think that – based on workload – if there are two or three of us, then we all 

listen intently. I can see where the workload would 

exponentially increase if you were in a non-normal 

situation. If one person was flying the aircraft as well 

as speaking, in a situation like that, and the other 

pilot was engaged in handling the non-normal situation then it could lead to an extremely increased 

workload.

Requires Extra Crew Resource Management

We really have to be attentive going anywhere 

in South America. When we’re coming off our rest 

breaks, a lot of captains want even the pilot coming 

off rest up there 30 or 45 minutes prior [to landing]. 

They have to be wide-awake and fully functional so 

they can see what’s going on. Coming into the U.S., 

most guys say 30 minutes is fine because it’s so easy 

to understand and it’s routine. 

I go into Brazil two or three times a month, so it’s no 

big deal; I know what to anticipate; otherwise, that 

26 Just as the right hand is dominant for many people, there also is ear dominance for hearing.

extra 15 minutes really helps. If the weather is bad, 

and all of a sudden, we’re holding with everything 

else, now it takes everybody in the cockpit to help.

A Considerable Amount Explanation

Of the 20 respondents, 70% offered comments and 

participated in discussions. 

Nonroutine Situations Are Problematic

I’ve found that anything outside the routine, although infrequent, requires a considerable amount 

of time. I often ask ATC to repeat what they’re saying. 

We recently had an airplane in China that wanted 

the emergency equipment and it never came. The 

controller didn’t understand what they wanted, and 

neither did the emergency guys.

Requires Deliberate Listening

In the non-native English-speaking countries, we 

really have to listen, stop doing whatever else we’re 

doing, and listen to what they’re telling us so we can 

understand the clearance. A lot of times, I’ll pick up 

a pen or pencil in anticipation of what they’re going 

to say so I have a written backup. This is unlike the 

U.S., where they’re speaking to us as if in a conversation – and we just instantly go “Roger.” 

Requires Extra Crew Resource Management

From experience, we anticipate when it should 

come, what it should be; and when a clearance is 

given, everyone listens and someone will call out 

what he heard. Sometimes we take a poll among 

the pilots to see if they can decipher what was said; 

this requires a considerable amount of attention 

from everyone.

There Is a Learning Curve

I’ve been flying these areas a lot lately, so it’s gotten easier. If I’m flying with new guys, I really want 

to make sure they understand they don’t need to be 

doing anything else. They need to be paying attention 

to communication.

When asked whether their company made any effort 

to pair a new captain with a first officer who had been 

there a lot, several pilots offered the following comments:

I’ve flown an SAQ27 to Mexico City with two guys 

who have less than 100 hours both in the control 

seats. They’re trying to listen to what the controller is 

saying, but they’re not hearing the Spanish. They’re 

also trying to concentrate on flying the airplane, 

which isn’t natural to them yet. It gets tough for these 

guys. However, they are legal to do it.

When I fly with inexperienced crewmembers, I 

always tell them to listen slowly when trying to understand a controller – although they say four or five 

words, it sounds more like ten. So we all listen slowly 

27Type of aircraft
22 

to the whole thing, rather than what we would do 

in the States. In the States, controllers say the words 

and we understand them quickly.

Understanding Can Be Lost in Translation

I’m prepared for ATC to speak to other aircraft in 

their native language and then English to us more so 

in different parts of the world. I just steel up and plan 

ahead. We hear so many words that seem to mean 

something differently there. For example, “their,” 

“they’re,” “there;” “to,” “too,” “two” – numbers 

sound different. 

If I try to speak in Spanish, what if it’s terrible? I 

might be saying something and not know his interpretation. [When that happens] he’ll try and talk to 

me in Spanish and I just say, “I don’t understand.” 

So, I stop and ask in ICAO phraseology, “What do 

you want me to do?” Then, he’ll come back with the 

ICAO standard. 

With all that said, their communication skills are 

good; but it still requires a considerable amount of 

attention and being on the lookout at all times. As 

far as how much attention is required to understand 

what a non-native English-speaking controller is 

saying in English depends on where you are and on 

their accents.

A Moderate Amount Explanation

Approximately 69% of the 13 pilots provided written 

and oral comments. 

ICAO Phraseology Makes Understanding Easier

I would prefer to hear standard ICAO phraseology. 

But, on the rare occasions when there are no phrases 

to cover something – a clearance or deviation for 

weather, or to clear up his understanding of what I 

want, it becomes more difficult for ATC to express 

what they want to say and more difficult for us to 

understand what they’re trying to say. If they move 

away from ICAO phraseology, they’re a little bit less 

comfortable with the words they use, so I’ve got to 

listen up for nuances that will help me understand 

what they are saying.

Pilot Fatigue Exacerbates Attention

We certainly touched on something that causes us 

to realize another major factor or two that make it 

difficult. When you near the critical phase of flight 

– arrival and approach, having flown all night, last 

pilot on break just woke up, body rhythms are out 

of whack, and going to the flight deck – you need 

to understand what’s going on, be prepared to think 

quickly, process the weather, and have some attention for what ATC wants you to do. You have to ask 

the co-pilot, “Did you hear what he said?”

There Is a Learning Curve

Initially, a moderate amount of my time is spent 

trying to understand what the controller wants. But 

as I become more familiar with the wording and accents, it becomes easier and less attention is required. 

It also depends on the individual controller; some 

are easier to understand than some U.S. controllers 

are. A lot of what we’re talking about is small, in the 

overall picture, but big in a specific instance.

A Limited Amount Explanation

Of the four respondents who reported a limited amount 

of their attention is required to understand the English 

spoken by non-native English-speaking controllers, all 

made comments. 

English Ability Is Theater-Specific

It varies widely – it takes a lot of attention in some 

areas, while other areas are easy. I’ve found that if I 

listen the normal way, understanding is almost always 

there. As I’ve been exposed to an area more and more, 

it’s gotten easier. Anytime we’re dealing with a more 

experienced controller, it’s easier. Accented English 

requires increased attention.

I think all controllers want to take the time to say 

it right – they don’t have the time. Even our controllers have gotten nasty with foreign carriers flying in 

here when it’s “say again, say again,” and then, “say 

again.” It’s understandable what they’re going through, 

and they’re frustrated with a pilot coming into our 

country and not immediately grasping the language 

of some controllers with a rapid-fire accent saying, 

“Do this, do that, do this.” You’ll hear it on both ends 

of the spectrum when you talk to the foreign pilots.

38b. What are the most troubling language-based 

problems you experienced with non-native Englishspeaking controllers?

Approximately 94% of the pilots commented on 

this question during the interview. Their responses were 

grouped together by related content and then arranged 

thematically. We identified five language-based problems 

involving issues ranging from accent to a failure to communicate. They are presented alphabetically in Table 12, 

followed by the respondents’ abridged comments. 

English Ability Is Theater-Specific

I think that poor radios, English as the second language, and then different phraseologies in the poorer 

countries will be with us for a long time. We will not 

easily understand the controllers’ pronunciation of 

words until their equipment improves. 

Also, some countries don’t have the airway structure [that is] anything like what we have. They have 

very few airways – so there are a lot of airplanes on 

those airways – and there is hardly ever a break in 

the action. It just seems like it’s always peak traffic. 

They’re giving out instructions very quickly. If we 

have a problem and need to get something repeated, 

it’s hard to cut in to tell them. Meanwhile, we’re not 

able to conform to whatever it is that they want us 

to do. Meanwhile we’re still on our way.
23 

Misunderstandings

Call Sign

To detect our call sign sometimes in Latin America 

or South America requires us to listen closely to catch 

it. When we call in the first time, controllers respond 

back with the phonetics “Delta Alfa Lima” instead of 

“Delta” or Uniform Alfa Lima for “United.” It takes 

us by surprise and we may miss the call. We hear 

some different dialects, and the way our call sign is 

pronounced in some places is sometimes hard to 

understand. They may not have seen or are used to 

our ninety-nine one or ninety-nine Alfa call signs. 

These call signs aren’t that common yet.

Clarity of Message

The most troubling language-based problem I experienced with non-native English-speaking controllers 

is usually the clarity of what they mean and what I 

hear. Clarity is what is meant by the transmission – for 

example – “cleared direct” as opposed to “cleared 

present position direct” or “cleared to,” it’s the clarity 

of what fix it is.

There is a conflict in meaning of certain ATC 

phraseology, such as “line up,” “line up and wait,” 

and “cleared to follow behind.” I don’t even think 

that was ever in our books; we can see that some of 

the things they say have certain meaning to them, 

but they might have a different meaning to us.

Multiple Languages on Frequency Diminishes 

Situational Awareness

When controllers speak to other aircraft in their 

native language, I don’t have a clue as to what 

they’re saying. It reduces my situational awareness 

as to what’s going on in the pattern, or if there are 

weather situations. I’m wondering, is that something 

important I might need or want to know about? The 

problem is more than annoyance at the chatter; it’s 

less situational awareness and misunderstanding 

a clearance, due to the fact that sometimes I don’t 

understand controller/pilot communication in their 

native language; and quite often, when they point 

out or clear us to somewhere, it is confusing.

Nonstandard Phraseology

We need to deviate from the standard when there 

is an emergency or if someone misunderstands a 

transmission. The language problems come up when 

controllers have to use nonstandard ICAO phraseology – when there is a need to deviate from standard, 

making sure it is understood. 

Similar-Sounding Words

Even though I already know that a clearance is 

coming, sometimes it’s very difficult to know and 

understand what was said. We may have to listen 

to it two or three times before somebody hears it 

for what it was. But we still read it back and get the 

affirmation that was in fact what ATC said. 

Clearances and reroutes to fixes and NAVAIDs that 

are non-English based and understanding altitude 

or number-based clearances can cause problems. 

Waypoint names often are not common words. I have 

difficulty distinguishing one from another – especially 

if they look alike or sound alike. When that happens, 

I may have to request it be spelled phonetically. 

What I find even more troubling is the “two three 

zero,” and “three two zero” clearances given by some 

non-native English-speaking controllers, because the 

“two” and the “three” become almost blurred, sound 

alike. I have to clarify it – “was it two one two three 

zero; or was it “three one two three zero?”

Translation

In translating the native language to English, or 

English to their language, there may not be a word 

to fit [the meaning or intent]. We had a flight not 

long ago in South America where the pilots wanted 

to burn some fuel to get down to the max landing 

Table 12. Language-Based Problems Arranged Thematically. 

Language-Based Problem Issue

English Ability Is Theater-Specific 

Asia 

South America 

The “Stans” 

Misunderstandings 

Call Sign 

Clarity of Message 

Multiple Languages on Frequency Diminishes Situational Awareness 

Nonstandard Phraseology 

Similar-Sounding Words 

Translation 

Pilot Controller Interactions 

Failure to Communicate Results in Frustration 

Readback/Hearback Loop Provides No Assurance 

Repeating Transmissions Without Variation 

Uncertainty Regarding Mutual Understanding 

Speech Characteristics 

Accent 

Decoding What Was Said 

Pronunciation 

Speech Rate 

Unexpected and Complex Clearances 
24 

weight. They tried to explain that to the controller 

enroute, but the controller could not understand the 

English words to translate them into his language.

Pilot Controller Interactions

Failure to Communicate Results in Frustration

If a point is not conveyed or understood, we either 

ask for a repeat or have them say it again. Often, 

I find there is frustration as controllers will speak 

louder or talk faster.

Readback/Hearback Loop Provides No Assurance

The most troubling thing I see is pilots using the 

controller’s hearback to correct their readbacks. My 

suggestion is that if pilots don’t understand what they 

heard, they should just say, “Say again.” Say again 

is the proper way.

The hearback/readback problem is significant. 

We had a problem where a pilot was expecting a 

clearance onto a runway. He was given a hold short 

clearance and said, “Roger position and hold.” He 

was expecting line up and wait; but didn’t get that, 

but that’s what he read back. Relying on ATC to 

correct you is not a good idea. It causes me great 

uneasiness because I say to myself, “Did I really read 

back what he told me to do?”

Repeating Transmissions Without Variation

One problem I have experienced is controllers 

who repeat the same garbled English multiple 

times instead of varying it. For example, I’m given a 

radio frequency and say, “Say again;” and they say 

it exactly the same way again. “Say again,” they’ll 

say it exactly the same way the third time instead of 

getting another person to say it, vary the pace, pitch, 

or doing something different. 

Uncertainty Regarding Mutual Understanding

The most troubling parts for me would be frequency 

changes, altitudes, and clearances. It’s so busy in 

many parts of that world, it’s hard to get back in, 

and say, “Say again.” Once I get a clearance, I try to 

understand and make sure I have it; it’s a question 

of “Is he hearing what I’m saying, and vice versa?”

Speech Characteristics

Accent

It’s my experience that language-based problems are 

geographical – a native language either lends itself to 

speaking English in a heavy accent or not. A strong 

accent is not only bad in Common English; it is bad 

in ATC English. I will have difficulty understanding 

heavily accent English or very thick-tongued English. 

Decoding What Was Said

The most troubling language-based problem with 

non-native English speaking-controllers is that we just 

can’t understand each other. It’s been my experience 

that if there is a query coming from our airplane, we 

don’t get a response because of a language barrier. 

Just making ourselves understood is problematic in a 

non-normal or unexpected situation. Understanding 

what they are telling us – flight levels, headings, and 

clearances – affects the safety of flight.

VORs, NAVAIDS, and Waypoints

One big area that keeps coming to my mind is that 

a lot of NAVAIDs look alike and sound very similar; 

and I have to re-verify them. Everyone talks about 

this problem.

Pronunciation

It seems to me that the pronunciation and sentence structure – like Spanish – are backwards from 

English in the way [native speakers] fix their words. 

The inability of a controller to pronounce ICAO 

standard phrases is a problem in any non-native 

English country. If the phraseology is nonstandard, 

then pronunciation is a bigger problem.

The way fixes are pronounced in a controller’s native 

language makes it seem as if I never heard them. In 

other words, we don’t pronounce the word that we 

see in front of us the way they pronounce it; and in 

Japanese, it’s the “l’s” versus “r’s.” 

The differences in pronunciation are basically the 

most troubling problem. It is more difficult when 

we don’t realize that they didn’t understand us, or 

they don’t realize that we didn’t understand them. If 

I know that we didn’t understand, I can try to clarify 

that issue and eventually get it clarified and visa 

versa. If it’s so subtle that everyone misses it, we’re 

on different pages, it’s allowed to stay that way, and 

that’s when the most trouble occurs.

Speech Rate

One of the big language-based problems is that it 

is hard for us to understand when ATC talks too fast. 

Sometimes it can be that they’re trying so perfectly to 

do the vowels that we’re listening faster than they’re 

talking; we’re just not on the same page.

Unexpected and Complex Clearances

The complexity of clearances can be problematic 

that are unexpected such as reroutes, change of fix 

or waypoint, altitude restrictions, speed changes, 

etc. For example, I received a clearance that had 

a specific problem while we were on the ground. 

It was the initial clearance and it was very difficult 

because we could not understand what ATC wanted 

us to do. We never were certain that we had it right; 

but at the same time, we were trying to prepare the 

airplane, get the engines started, and things like that. 

That was the most troubling language-based experience with a non-English controller. 
25 

38c. How often have you heard non-native Englishspeaking controllers use jargon or slang that was 

difficult to interpret? 

As shown in Table 13, 85% of the pilots reported they 

rarely experienced difficulty interpreting the jargon or 

slang they heard spoken by non-native English-speaking 

controllers. Approximately 13% of the respondents occasionally heard it while one pilot said it occurred frequently, 

although they provided no examples. Their compiled 

comments from the written and interview portions of 

the questionnaire are included below.

Rarely Explanation

Forty-one respondents reported they rarely heard slang 

or jargon while monitoring their radios. Of these pilots, 

49% offered comments that were combined by theme 

and abridged.

Never Heard Any Jargon or Slang

My perception is they typically don’t use a whole 

lot of English outside of ATC, so they aren’t going to 

be too willing to use slang. I wouldn’t understand it 

if they were saying it in their native language.

Heard a Little Jargon and Slang and Understood It

Any jargon or slang that I have heard I knew and 

understood. Sometimes I hear phrases such as “speed 

up.” I’m not used to hearing “speed up.” I know 

“accelerate to,” or “increase airspeed,” or “maintain 

250 knots.” I find that non-native English-speaking 

controllers tend to avoid using anything that’s outside 

of the norm as much as possible. They don’t want us 

to be confused, and they don’t want to be confused 

by us; so most of the time, we stick to a script and 

we don’t use jargon or slang; they understand that’s 

not permitted.

Only U.S. Controllers Use Jargon and Slang

I only hear jargon or slang in the U.S. It should be 

troubling because this is what a non-native Englishspeaking pilot hears flying into the U.S.; they don’t 

speak English as a primary language and they aren’t 

going to be too willing to use it.

European Controllers Use Jargon and Slang

Most of the jargon and slang that I hear is in Europe, 

and they know what they’re saying. Sometimes we 

hear, “Follow the lights” when we turn off the taxiway. And we’re going, “What, which lights?” What 

they’re talking about are the taxi lights – the lights 

lead us to where they want us to go and are turned 

off when they want us to stop. It actually works very 

well, by the way.

Occasionally Explanation

Of the six pilots who reported they occasionally heard 

controllers use slang or jargon, 33% offered comments 

that were edited. 

I’ve heard, “fly to,” and sometimes numbers are 

given without specification on whether they are 

“airspeeds,” “altitudes,” or “headings.” Going back to 

earlier experience, as I’m crossing an FIR28 boundary 

in the Middle East and expecting to get my clearance 

across, the controllers say “continue;” and that is 

equivalent to “cleared as filed to your exit point.” I 

need to understand that is what they are telling me 

by saying, “continue.”

Frequently Explanation 

One respondent reported he frequently heard slang 

or jargon while monitoring pilot/controller communications. He gave no examples of jargon or slang.

38ci. Please write some examples of the jargon that 

was difficult to interpret.

Presented in Table 14 are the five examples of jargon 

generated by the pilots. Although others were mentioned 

during the course of the interviews, only those given in 

response to this question are represented.

28 Flight Information Region

Table 13. Frequency of Jargon or Slang Usage by Controllers Not Interpreted Easily by U.S. 

Pilots. 

Frequency of Jargon or Slang Not 

Easily Interpreted 

Number 

of Pilots Issues 

Rarely (less than 10% of my time 

monitoring pilot/control communication) 

41 

Never Heard Any Jargon or Slang 

Heard a Little Jargon and Slang and Understood It 

Only U.S. Controllers Use Jargon and Slang 

European Controllers Use Jargon and Slang 

Occasionally (between 10-24% of my time 

monitoring pilot/control communication) 6 

Frequently (between 25-74% of my time 

monitoring pilot/control communication) 1 

Often (between 75-90% of my time 

monitoring pilot/control communication) 0 

Without fail (more than 90% of my time 

monitoring pilot/control communication) 0 
26 

38cii. Please write some examples of the slang that 

was difficult to interpret.

Presented in Table 15 are two examples of slang 

provided by the pilots. In both cases pilots experienced 

difficulty understanding what the controller had said 

to them.

DISCUSSION

During one part of the interview, a pilot answered a 

question that expressed the sentiment of many pilots. 

The question was, “When controllers are speaking in 

their native language to their own pilots, is that much 

of an issue for you?” to which the pilot replied, “I feel 

out of the loop because I don’t know if the foreign carrier coming in might be conflicting traffic for me. You 

kind of know what the controller’s asking them and 

what they’re acknowledging. So, everybody’s sort of on 

the same sheet of music. I really have no idea what the 

controller might be asking the pilot. It makes me a little 

uneasy; for the most part, I guess they’re keeping things 

sorted out, I hope.”

International Flight Experiences Among 

Participants

In the three months preceding the interviews, the 48 

U.S. pilots listed 74 geographical areas they had flown 

through, with Canada, England and Mexico frequented 

by at least 33% of the pilots. They landed their aircraft in 

47 different countries or regions during that time period. 

Within the 30 days preceding the interviews, 83% flew 

an average of five international flights, including multiple 

flights to Costa Rica, Guatemala, and Venezuela. Clearly, 

as a group, the pilots had diverse flight experiences.

English Language Acquisition and Usage

All of the U.S. pilots listed English as their first language and noted they had learned to speak it informally 

at home prior to entering elementary school. Also, they 

reported English as the language spoken most frequently 

at home. Approximately 60% reported they neither spoke 

nor understood any languages other than English. For the 

remaining pilots, many indicated they spoke/understood 

some French, Spanish, or both. In addition to Spanish, 

one pilot also spoke/understood German, and one 

spoke/understood Spanish, French, and Portuguese. 

When asked about their listening and speaking skills, 

nearly 80% of the pilots reported no dominance of 

one skill over the other.

Language Experiences in Non-Native EnglishSpeaking Airspace/Airports 

There were 21 different non-native English languages 

heard by pilots during their international flights, with 

Spanish and French listed 22.60% and 19.86%, respectively. Chinese, German, Italian, Japanese, Portuguese, 

and Russian were listed between 6.16% and 8.90%, while 

the remaining 14 languages varied in presentation from 

0.68% to 2.74%. 

When asked how they would rate their overall nonnative English-speaking language experiences, only 17% of 

them rated it as either very positive or positive, 31% rated 

it as neutral, and 52% reported it as negative. Among the 

pilots with a favorable rating, notably their admiration 

for controllers being able to speak English was apparent 

(especially when many of the pilots only spoke English). 

Likewise, pilots viewed flying outside the U.S. as a learning experience offering them the opportunity to develop 

their piloting skills and become more culturally aware. 

The pilots who expressed a more neutral viewpoint 

also noted the opportunity for personal and professional 

development; they also took the stance that both pilots 

and controllers have difficulty understanding one another. The example of a pilot who had difficulty getting 

the controller to understand that he could not descend 

because there was an aircraft beneath him displayed on 

TCAS highlighted the problem. Trying to explain TCAS 

to the controller may have resulted from the controller 

lacking an understanding of aircraft electronic systems 

such as TCAS, the English language, or both.

Among the pilots who reported negative experiences, 

there were several factors supporting their rating. These 

factors involved the frustration of hearing different languages on their radios that restricted situational awareness, 

and more effort making repeated calls to ATC coupled 

with diverting more of their attention to listening to what 

the controller said to assure understanding.

Only 25% of the pilots reported they rarely experienced problems related to communication problems 

in non-native English-speaking airspace/airports, while 

another 52% reported occasional problems. Finally, 23% 

Table 14. Examples of Jargon. 

Jargon 

“I call you back” vs. “stand by” 

“Fly to” 

“Continue” on initial contact at FIR or UIRa in the Mideast rather than “cleared as filed” to exit point 

“Redirect” vs. “cleared direct” 

“Breakout” vs. “go-around” 

a

Upper Flight Information Region - ICAO 

Table 15. Examples of Slang. 

Slang 

“No sea wet” [no sweat] 

Native language “yes” or “no” vs. “affirmative” or “negative” 

 
27 

of the pilots indicated 25% or more of their interactions 

with non-native English-speaking controllers resulted in 

communications problems. 

Overall Non-Native English-Speaking Language 

Experiences

Professional Growth and Development

Only 17% of the pilots viewed traveling into countries 

with controllers whose English language skills varied as 

a positive learning experience. Initially, it was difficult, 

but as they completed more flights, learning occurred, 

and what once was viewed as unintelligible and difficult 

became manageable. With each flight, pilots developed 

expectancies derived from understanding exactly what it 

was that they experienced. Because controllers speak in 

English and the local language, pilots learned some of 

what was said in that language because it was repeated so 

frequently. As they became more seasoned, they valued 

their accomplishments.

The remaining 83% discussed the factors that led them 

to report their experiences as neutral (31%) or negative 

(58%). In particular, accented English and pronunciation 

are problems for them, as are the influences of different 

cultures on controller proficiency. When combined with 

multiple languages on frequency, situational awareness 

was adversely affected, as was identifying turn-taking as 

an integral part of the communication protocol. Each is 

summarized below.

Accent and Pronunciation Are Problems

Pilots reported that countries with close ties to the 

U.S. or U.K. seem to have controllers who have a better 

understanding of English. English, unlike most other 

world languages, has a different stress and rhythm pattern. 

Whereas other languages give equal time to pronounce 

syllables (regardless of whether or not they are stressed), 

in the English language, equal amounts of time only 

occur between stressed syllables; unstressed syllables are 

spoken very rapidly. Consequently, there is a negative 

transfer that occurs when listening to languages other 

than English. The farther removed the language is from 

English, the more difficult it is to process and understand. 

In particular, accent and pronunciation create problems 

for U.S. pilots, especially waypoints, fixes, company name 

as part of the call sign, and numbers. 

Cultures Differ

Some of the pilots’ perceptions were that controllers 

and pilots from poorer countries generally display less 

comprehension of English, are difficult to understand, and 

may prefer to communicate in their native language when 

the opportunity arises. If U.S. pilots ask a question about 

the communications, if there is a problem or concern, at 

times, these controllers fail to answer them. The lack of an 

acknowledgment may be due to the controllers’ insufficient 

English language skills, their preference of speaking in 

their native language, or they are simply ignoring the pilot. 

Another factor the pilots discussed was whether or 

not the culture supported developing English language 

skills of their citizens. In Europe, children learn English 

as a second language as part of their normal schooling. 

In other countries, English is taught on a limited basis, if 

at all. Likewise, the proficiency of the learner is based on 

individual differences. Some are better than others are, 

although sharing the same educational opportunities. 

The better ones seek jobs in the private sector because 

they can double their salaries over that of the wages of 

an air traffic controller. 

Communications in a Multilingual Environment 

Reduces Situational Awareness 

When non-native English-speaking controllers talk to 

local pilots in their native language, pilots who do not 

know that language cannot comprehend the conveyed 

information and experience limitations to their situational awareness. U.S. pilots would rather not make 

inferences or assumptions regarding actions by other 

aircraft in their proximity and prefer knowing how that 

information could affect them. Their ability to anticipate 

diminishes as expectations derived from party-line communications decrease.

Radio Protocol Is Lost in a Multilingual Environment

Listening to a combination of English and the local 

language deters from the radio cadence of turn taking. 

In the English language when a speaker finishes talking, 

there is a rising-falling intonation and silence signaling 

the listener the end of the utterance. If a question is 

asked, there would be a rising intonation at the end of 

the utterance. Unfortunately, pilots unfamiliar with the 

language cannot follow along and, not knowing when the 

utterance will end, are at a loss regarding when they can 

make a call or if the controller was calling them. Often 

they miss hearing their call signs.

Effects of Non-Native English-Speaking Language 

Differences on Pilot Workload

Increases Workload

One factor cited by pilots that increased their workload 

was the apparent difference in controller English language 

proficiency. Generally, there is the slowing of decoding 

skills – mapping of sounds and silence to detect meaning 

from nonsense to detect their call sign, standard phraseology, and numbers into meaningful utterances. When 

controllers do not speak English very well, transmissions 

have to be repeated many times for comprehension to 

occur. Pilots cannot rely on transmissions to other pilots 

to facilitate decoding since they do not understand what 

was transmitted to local pilots in their native language. 

Prinzo, Hendrix, and Hendrix (2008) report U.S. controllers and non-native English-speaking pilots exchange 

more transmissions than when both the controller and 

pilot are native speakers of English.
28 

A second factor was exertion of more effort to ensure 

understanding the intent of the controller’s transmissions from the phraseology used. As noted in Prinzo, 

Campbell, and Hendrix (2010), ATC phraseology such 

as “cleared direct” is not limited to one meaning. Any 

misunderstanding will increase the workload for both the 

pilot and controller. To resolve ambiguity often requires 

the exchange of multiple transmissions, as opposed to a 

single one. In such situations, everyone’s workload goes 

up with all the repeated radio calls for clarification. Because of the higher workload, it is harder to understand 

the non-native speaker’s English. 

A third factor was actively listening to communications between non-native English speakers arising from 

hearing multiple languages on the radio. When controllers and pilots speak in a language other than English, 

there is a reduction in U.S. pilot situational awareness 

caused by not fully understanding ATC communications presented over an open party line. ATC party-line 

communications provide a valuable piece of information 

not presently found on a traffic and collision avoidance 

system (TCAS) – that of intent. By listening to controllers issuing instructions, clearances, traffic, and weather 

advisories to other pilots, combined with TCAS, pilots 

develop a more comprehensive analysis of the airspace 

around them. When communications degrade, they 

experience a partial loss of this situational awareness that 

can be unsettling. They try to piece together the “who,” 

“what,” “where,” “why,” and “when” to determine how 

their flight may be affected from partial information. 

Fourth, these communications when combined with 

busy radio frequencies, delay completion of other normal 

station-keeping functions, especially during a critical phase 

of the flight when some crewmembers experience difficultly communicating and understanding the controller. 

Requires Added Attention and Concentration

Decoding a message from a non-native Englishspeaking controller requires increased concentration 

and attention because the controller’s dialect, accent, 

pronunciation, inflection, and speech rate affect linguisticprocessing of the voice stream. As noted in Prinzo, et al. 

(2010), until pilots learn to associate particular words with 

specific sounds of a foreign language, they will experience 

difficulty with that language.

Communication in a multilingual environment also 

demands more attention and increased concentration 

to discern what was said from what was expected. As 

noted in Prinzo and Campbell (2008) in preparation for 

a flight, pilots review their flight plan, maps, charts, and 

other materials in addition to talking with other pilots 

who recently flew the same flight and their flight crew. 

All of this information, along with their prior knowledge 

and preflight preparation, becomes integrated and form 

a series of episodes with an explicit beginning and end 

action sequences (e.g., scripts, Schank & Abelson, 1977). 

The quality of these mental representations is based on 

expertise – pilots with many flight hours for a particular 

route have well-developed and clear expectations about 

the order in which ATC will deliver instructions and 

clearances, as well as the contents of these speech acts. 

They anticipate the type of a clearance they are going 

to receive to facilitate understanding and then listen for 

the confirmation of their expectation. They may have 

the message repeated to ensure understanding. If there is 

incongruence, the pilot puts forth a request to have the 

message repeated to clarify any uncertainty.

Unfortunately, regional differences in English language 

proficiency may direct attention to decoding processes 

when flying in non-English-speaking countries. Pilots 

expect problems and discussed the differences in language 

skills among controllers according to phase of flight 

– whether they were in the en route or arrival environment. The amount of radio communication was factored 

in – when radios are busy with consecutive calls to and 

from ATC, more attention is diverted to interpreting 

and understanding what was said. Because of the added 

attentional demands placed on them when engaged in 

ATC communications, many pilots try to complete much 

of their station-keeping tasks at the cruise altitude (e.g., 

all briefing items, FMS entries, coordination with flight 

attendants) so they can allocate more of their attention 

towards listening to ATC. When they begin their descent, 

both pilots focus on what is being said so they understand 

what is taking place around them with other aircraft. 

Workload Related

TCAS Cannot Remedy the Loss of Situational Awareness 

Due to Multiple Languages on Frequency

Pilots have come to depend upon their TCAS to aid 

situational awareness when in non-native English-speaking airspace because of the language barrier. Although 

systems like TCAS were not developed for navigational 

purposes, some pilots use its information to request 

changes in altitudes and speeds based on separation 

minima. The problem is that neither a complete nor an 

accurate picture of all aircraft is presented on the visual 

display within the selected range.29 Still, it provides some 

useful information and is a backup tool when they are 

unable to understand ongoing communications on the 

radio due to the language barrier or radio coverage.

Advanced Avionics Offer Possible Solutions to the 

Language Barrier

The NextGen system will provide digital communications to flight crews in multiple formats (e.g., text, 

graphics). Presently in use are several early deployments 

of digital data transfer systems such as the ControllerPilot Data Link Communications (CPDLC) system30

and the Automatic Dependent Surveillance systems (e.g., 

29The requirement for an aircraft to have a TCAS or similar aircraft collision 

avoidance systems instilled is determined by the country of registration.

30 CPDLC is defined in the pilot controller glossary as “A two-way digital very 

high frequency (VHF) air/ground communications system that conveys textual 

air traffic control messages between controllers and pilots.”
29 

ADS-Broadcast,31 ADS-Contract32). CPDLC is currently 

used by the FAA’s Advanced Technologies and Oceanic 

Procedures (ATOP) Ocean21 system to send electronic 

messages between oceanic controllers and pilots prior to 

their entry into the U.S. 

Clearly, one benefit of CPDLC is improved information 

transfer. It provides pilots an alternative to voice communications for receiving information controllers have 

difficulty conveying in understandable English. A second 

benefit is a reduction in pilot and controller workload: 

neither will have to repeat a transmission, since the message is available for viewing on a visual display. A third 

benefit is the redistribution of attention to operational 

and procedural tasks. Trying to decode accented English 

diverts attention from other tasks as pilots (and controllers) attempt to understand each other.

Although CPDLC was originally developed for routine communications, pilots expressed concern with the 

language proficiency skills of controllers and whether 

they would be able to communicate effectively during 

emergency conditions. As noted by several pilots, “How 

would I tell the controller I had a problem – a cabin fire, 

engine fire, or terrorist attack, or something like that in 

English?” Developers and policymakers may want to 

revisit the applicability of CPDLC for emergency and 

off-normal operations.

While CPDLC will not remedy the loss of party-line 

information U.S. pilots experience when communications occur in languages other than English, the ADS-B 

system provides much of the missed information. It 

provides pilots with traffic graphically displayed in real 

time of aircraft similarly equipped. Call signs, trajectories, position, altitude, current heading, etc., are several 

pieces of information pilots have available for display to 

augment and update their situational awareness. These 

NextGen applications will enhance present-day operations in oceanic airspace as more aircraft are equipped 

with these avionics.

When in non-English-speaking countries, information from the automated terminal information service 

is heard in the local language and then in English. It 

is presented as a continuous transmission, and pilots 

often listen to it many times to extract information. It 

is a very time-consuming task that diverts the pilot’s 

attention and increases workload, especially if the pilot 

flying also has to listen to it. ATIS information could 

be uplinked to onboard avionics and pilots choose the 

mode of presentation. 

Frequency of Communication Problems

Only 25% of the pilots reported they rarely experienced 

communication problems during their interactions with 

controllers, while 75% said more of their interactions 

31 ADS-B provides pilots real time traffic on radar-like displays to enhance 

their situational awareness.

32 ADS-C allows establishment of position-reporting contracts between ground 

systems and an aircraft’s avionics.

involved communication problems. Some pilots used 

individual flights as the basis for their response, whereas 

others examined all of their flights over time. The degree 

with which these communication problems arose appeared to be related to where pilots flew – some parts of 

the world were more problematic, as were the types of 

problems they experienced; however, problems occurred 

everywhere. In some cases, the problems stemmed from 

faulty equipment. In others, it was country-specific, and 

the regional culture’s influence on the controller’s ability 

to communicate in English. Pilots reported the controller’s 

accent or pronunciation of waypoints, fixes, numbers, or 

words as sources. Whatever the case, whenever a communication problem occurred, flight deck operations slowed 

down as the flight crew diverted attention from other tasks 

to understand what the controller said. 

Variability in English Language Skills of Pilots and 

Controllers 

When asked whether English language skills are comparable from one non-native English-speaking country/

airport to that of another, 61% of the pilots reported 

some countries have better English-speaking pilots than 

others, as was the case with their controllers. The pilots’ 

English is consistently better than that of the controllers. 

Notable differences resided in accents. 

Several pilots commented that a key factor that determined proficiency in English was learning it early in life. 

From their flight experiences, they reported there is a wide 

skill level of English speaking from country to country, 

and even from individual to individual. Furthermore, the 

pilots suggested countries placing a strong emphasis on its 

children learning English as a second language, beginning 

in elementary school, generally spoke English better than 

a person learning it as an adult. 

Their perceptions are partially supported by research 

into second-language learning. There is much controversy 

regarding “critical periods” for language-learning, depending upon which aspect of language is investigated (e.g., 

phonology, vocabulary, grammar). For example, research 

performed by Flege, Mackay and Piske (2002) showed 

that dominant Italian bilinguals had detectable foreign accents when speaking English, but early bilinguals (English 

dominant) had no accents in either language. SebastiánGallés, Echeverría, and Bosch (2005) report learning a 

second language once the phonology of the first language 

is stored in memory can reduce sensitivity to distinguish 

new sounds present in the second language. Many factors 

influence whether a person becomes proficient in a second 

language (motivation, maturity, learning style, etc.)

Other key factors included the level of proficiency 

tended to compensate for stronger accents, and the busier 

international airports tended to attract controllers who are 

more fluent in English. Communicating with Englishspeaking pilots reinforces their basic skills and encourages 

them to speak more frequently which, in turn, increases 

their proficiency.
30 

Factors Contributing to the Intelligibility of NonNative English-Speaking Controllers

About 75% of the pilots indicated they had to work 

harder to understand non-native English-speaking controllers. Regardless of whether native or non-native in 

the English language, the more unintelligible the speaker, 

the more difficult it was for the pilots to understand 

what was spoken. Voice characteristics such as accent, 

pitch, pronunciation, and speech rate each contribute to 

intelligibility and the ease with which pilots understand 

controllers.

On international flights, it is not uncommon for pilots 

to hear five or more different accents as they travel from 

one country (or state) to that of another. Controllers 

with higher-pitched voices are not only difficult to listen 

to but also hard to understand. Add to that their varied 

pronunciations of waypoints, fixes, and numbers coupled 

with a rapid speech rate, and it is no wonder that pilots 

will ask for repeats in the form of a say again, confirmation, or verification of some or all of the transmission. 

Factors Contributing to the Understandability of NonNative English-Speaking Controllers

The responses of the pilots were organized into three 

broad themes: Voice Properties, Delivery Technique, and 

Radio Equipment. 

Voice Properties

There are individual differences in the voice properties of all speakers. We use these unique qualities to 

distinguish between speakers as male or female, child or 

adult, native, or foreign, etc. When listening to people, 

we can also determine their geographical area of primary 

residence by country and region. 

With bilingual and multilingual speakers, oftentimes 

the dominance of their first language carries over into the 

other languages that they speak. Because some languages 

have shared properties, they are easier to learn and understand than languages sharing few to no commonalities. 

For example, English, French, German, and Spanish 

belong to the same Indo-European language family, 

making them easier to learn as a second language among 

the speakers of these languages. In contrast, speakers of 

languages such as Arabic (Afro-Asiatic language family), 

Japanese (Altaic/Isolate language family), and Chinese 

(Sino-Tibetan language family) are considered difficult to 

learn by native English (Indo-European language family) 

speakers and visa versa.

Notably mentioned factors affecting the understandability of non-native English-speaking controllers were 

their differences in accent, dialect, enunciation, pitch, 

and pronunciation. The proficiency of controllers was 

influenced by the opportunities they had to communicate with others in English. In particular, if controllers 

worked at busy international airports that contracted with 

English-speaking airlines, they had a greater possibility 

of hearing English and practicing their speaking skills. 

The more frequent these communications occurred, the 

greater the opportunity to practice English.

Another factor affecting understanding was whether 

controllers learned English as part of their early educational 

experiences. Controllers who learned English during 

early childhood had less influence of their first language 

on their English production. Although accented, it was 

not as apparent as the speech of a controller who learned 

English as an adult. 

Delivery Technique

U.S. controllers deliver messages in a particular cadence, which U.S. pilots are acclimated to. Likewise, 

native English-speaking pilots have a cadence that is 

understood by English-speaking controllers, though 

it may vary pilot-to-pilot, company-to-company, and 

country-to-country. Different messages have different 

melodies. When outside the U.S., pilots do not hear this 

expected “melody;” rather, they hear controllers who may 

place the emphasis on an unanticipated syllable, pause 

when unexpected, lack the voice contour for particular 

commands, and so forth. 

Cadence is separate from speech rate. Pilots reported 

that the controller’s speech rate was the biggest problem 

they experienced in communication. As traffic load 

increased, so did the rate of speech and the number 

of repeated transmissions. Some pilots perceived that 

controllers may speak faster, either to mask a lack of 

proficiency or to show off their proficiency. In fact, the 

ICAO Language Proficiency Rating Scale contained in 

Doc 9835 (ICAO, 2004) evaluates the fluency dimension 

of proficiency using tempo as one element of consideration – a faster tempo received a higher mark for fluency. 

Therefore, while learning English, controllers might 

be told to speak faster to obtain a higher score on this 

dimension. They may continue to speak quickly once in 

the control room, although they may be less proficient 

on other dimensions.

An interesting study conducted by Zhao (1997) argued 

that the perception of speech rate is highly subjective and 

influenced by context, language proficiency, memory 

capacity, listening habit, and processing strategy of the 

listener. In his study, the listener had controlled the rate 

at which auditory materials were presented by expanding, compressing, or not changing pause and syllable 

durations within a sentence. The findings revealed the 

development of individually determined, internalized 

ideal speech rates that listeners adjusted to a slower rate 

to improve their comprehension. As they became more 

proficient (or adapted to the speaker’s delivery style), 

subsequent speech rates increased without a decrement 

in understanding.

Thus, it might be best for controllers in the international airspace to speak slower to improve pilot comprehension. Also, they could pause after the call sign and 

after each instruction or clearance in the transmission. This 

might reduce the number of pilot requests for repetition.
31 

Radio Equipment

The pilots also discussed the sound quality of the 

broadcast contributed to the intelligibility problems 

during their international flights. If pilots cannot hear 

the controller’s voice clearly because of static, distortion, 

reverberation, hollowness, echo, or their combination, it 

will be difficult to extract the auditory component from 

acoustic noise. If they cannot disambiguate one sound 

from another, identifying meaningful words is unlikely.

Another problem was spotty radio coverage. In some 

cases, weather was a contributing factor, in others the 

radios may not have been monitored, whereas in others 

it was nonexistent. In these situations, party-line communication becomes valuable among pilots who share 

information with each other.

ICAO Standard Phraseology Usage by Non-Native 

English-Speaking Controllers

When flying in a non-native English-speaking country, 

85% of the pilots indicated that 75% or more of their 

interactions with controllers involved the use of ICAO 

standard phraseology during routine communications. 

Generally, non-native speakers know only the standard 

phrases and perform as professionals by not deviating 

away from these phrases. There was an exception, and 

that was in South America, where their pilots indicated 

more nonstandard communication. It may be part of the 

local culture’s influence. Several examples were provided 

that included, “You’re not cleared to land” and “continue” 

when calling approach.

Common English Usage by Controllers in NonNative English-Speaking Countries

Typically, interactions with non-native Englishspeaking controllers involve ICAO standard phraseology, although it can vary from country-to-country and 

individual controllers. Common English is usually used 

only by experienced controllers who are more familiar 

with English. Only 25% of the respondents reported 

controllers frequently (or greater) switch from standard 

phraseology to conversational or plain English. This 

generally occurs when controllers try to explain or verify 

a previously issued clearance. Whether or not controllers 

use Common English often depends on their previous 

successes (increases confidence) or failures (increases 

embarrassment). The more confident they become, the 

more likely they are to continue using it. The 75% who 

indicated they heard controllers communicate with them 

in Common English only occasionally or rarely added 

the controllers’ usage of Common English might be 

unconventional, but they make their point. 

Non-Native English-Speaking Controllers’ Ability 

to Communicate in Common English

Approximately 77% of the pilots described the controllers’ ability to communicate with them in Common 

English as either good (35%) or fair (42%), and another 

15% indicated it as poor. The remaining pilots did not 

select one of the response options; rather, they said some 

countries’ controllers were good, others fair, and some 

poor. As a group, none were terrible (although some 

individual controllers were so designated). 

When pilots fly in the U.S., they often informally ask 

controllers, “How’s the ride?” to learn whether there is 

any nearby turbulence at their altitude. This generally 

does not occur in other countries because many controllers would not know what the pilot was saying; they do 

not have any phraseology that includes the words “ride 

report.” If the controllers’ communication skills are only 

fair, their ability to understand and respond is limited to 

ICAO phraseology. Even among the better controllers, 

when off-normal events arise, it is not easy for pilots to 

understand what they are attempting to convey in Common English. One pilot said he’d rather have a problem 

in Canada or Europe (Germany) than in China, Japan, 

or in the Asian Pacific region. 

Amount of Attention Required for Understanding 

No one thought understanding non-native Englishspeaking controllers was effortless. In fact, 65% of the 

pilots reported either a considerable (42%) or a great 

(23%) amount of their attention was required to understand the English spoken by non-native speakers. Just as 

controllers’ English language proficiency increases as they 

speak it more frequently and gain confidence, there also 

is a learning curve for pilots and their listening skills. 

Just as the quality of the radio broadcast and equipment 

influence intelligibility, where they were, the degree of 

accented English, normal as compared with off-normal 

situations, availability of other pilots in the cockpit, as 

well as fatigue – all of these factors exert an influence on 

how well pilots understand non-native English-speaking 

controllers. 

Initially, pilots invest much attention separating the 

acoustic information from the auditory signal. How well 

they can make the separation depends upon the signalto-noise ratio that affects intelligibility. The greater the 

noise, the less intelligible the speech signal embedded 

within that noise (i.e., articulation index, see French 

& Steinberg, 1947; and Beranek, 1947). Several pilots 

mentioned possibly purchasing noise-cancelling headsets 

to improve intelligibility.

Pilots with limited international experience initially 

experienced greater difficulty and expended much attention understanding non-native English-speaking 

controllers, compared to pilots with more international 

experience. However, as they gained familiarity, intelligibility appeared to improve, as did their decoding and 

comprehension skills, making understanding easier and 

requiring less attention. 

As noted previously, most controllers use ICAO standard phraseology when speaking English and are effective 
32 

communicators. However, it still requires a considerable 

amount of attention and vigilance from pilots, especially 

when controllers revert to their native language.

The Most Troubling Language-Based Problems

The pilots were very open about discussing the language 

problems they experienced. For them, the controllers’ 

ability to communicate with them seemed specific to a 

geographical area where some controllers were more adept 

at English, and learning that language was supported by 

the government. Generally, pilots discussed the problems 

that arise from poor radios, the controllers’ ability to 

speak English as a second language, and their outcome 

on crew performance and flight safety.

Misunderstandings

Another group of problems resulted in misunderstandings. One problem involved the way controllers 

pronounced the call sign. Typically, it begins with the 

company name such as, American, Continental, Delta, 

United, and so on. However, some controllers used the 

phonetic alphabet for pronouncing the company’s threeletter identifier (e.g., alfa, alfa, lima for American Airlines). 

Another problem involved translating. In some instances, words do not exist in which to explain a concept 

or action, and either the pilot or controller may resort to 

nonstandard phraseology. An example was given of a pilot 

who needed to dump fuel to get down to the maximum 

landing weight, but the controller could not translate 

the Common English words spoken by the pilot into his 

language. There was a failure to establish the common 

ground of understanding between them. Misunderstandings also occurred when numbers sound similar to one 

another. Likewise, the names of waypoints and fixes in 

reroutes. Finally, the issue of controllers speaking to other 

aircraft in a language other than English interfered with 

their understanding of the situation near them. 

Pilot Controller Interactions

As part of resolving misunderstandings, pilots and 

controllers exchange additional transmissions in the form 

of requests for confirmation, verifications, and either full 

or partial repeats. If the pilot incorrectly reads back the 

contents of the previous controller transmission, there is 

the expectancy that the controller will hear the mistake 

and correct it. However, this assumption is faulty in that 

there is no assurance that the mistake will be acknowledged 

and corrected, especially when the English language skills 

of the controller may lack proficiency.

The failure to communicate can be very frustrating for 

both participants – repeating the information using the same 

phraseology only saying it louder or faster is not adequate; 

neither is dismissing either the readback or request for clarification. When uncertainty exists between what the controller 

says to do and the pilot’s subsequent action, the information 

may need to be restated differently. This would require more 

than a basic level of English language proficiency.

Speech Characteristics

Language-based problems are geographical, in that the 

native language either is heavily accented (compared to 

“broadcast English” on U.S. television programs), and the 

speech rate can make it difficult to be understood. The pilots indicated that the two most troubling language-based 

problems with non-native English-speaking controllers 

were difficulty in understanding and non-response due 

to a language barrier. One common problem discussed 

among pilots was the accent placed on words and names 

of navigation aids by controllers in their native language 

do not necessarily correspond to how these same words 

and fixes are pronounced in the U.S. Since many waypoint names may look alike and can sound very similar, 

pilots ask controllers to re-verify them. The differences 

in pronunciation become exacerbated when pilots do not 

realize they really did not fully understand the transmission, process the information differently than what the 

controller expected, and it goes undetected. If either one 

realizes they are operating on different premises, it can 

be resolved. 

Unexpected and Complex Clearances

Receiving unexpected and complex clearances can be 

problematic (such as reroutes or altitude restrictions). 

This is especially true when pilots are multitasking while 

either taxiing to a runway or immediately after takeoff. 

Slang or Jargon Usage by Controllers

For the most part, if controllers were using jargon 

or slang, it would be in their primary language and 

many of the pilots would not understand it. In fact, 

85% of the pilots said controllers avoid saying anything considered nonstandard because of their limited 

English skills.

Mitigation Strategies and Techniques

1. Develop a visual aid to facilitate communications 

with non-native English-speaking controllers that lists 

the names of fixes with their phonetic spelling and 

identifier. One airline developed a four-page visual 

aid for Spanish.

2. Talk slowly and deliberately to ATC to make understanding easier. Decoding one language into that of 

another is not an automatic process and takes time 

for less proficient speakers.

3. Learn to count in the languages of the countries you 

frequent.

4. Try to complete station-keeping tasks at cruise altitude 

(e.g., all briefing items, FMS entries, flight attendant 

issues) so more attention is directed to listening to 

ATC when on descent.

5. Keep communications to very basic ICAO phrases. 

Any nonstandard requests are often difficult for nonnative English-speaking controllers to understand.

6. Wear a headset and put in an earpiece instead of 

listening to external speakers.
33 

Technological Solutions to Global Issues

1. Globally inconsistent English language proficiency 

among pilots and controllers may be reduced by 

developing ATC training software packages that display the speaker’s speech samples against an accepted 

universal standard to improve English skills. Secure, 

online language proficiency testing certified to meet 

ICAO requirements could ensure that all states meet 

the same training standards provided by flight schools, 

ATC academies, and training centers. Testing would 

include assessing English-language proficiency in 

reading and writing, as well as listening and speaking 

skills within a cross section of normal and off-normal 

circumstances.

2. Multi-linguistic environments restrict effective information transfer that reduces situational awareness, 

diminishes pilots’ expectations derived from the party 

line, and impedes the established radio protocol. The 

use of Automatic Dependent Surveillance applications 

that provide call signs, current and projected altitudes, 

speeds, headings, and route information for aircraft in 

proximity to “ownship.” Also, a user-selectable ATIS 

uplink could be made available in English and the 

local languages.

3. Unfamiliar, heavily accented English slows decoding 

and understanding processes. Intelligibility degrades 

when coupled with poor radio equipment and 

weak broadcast strength. It is possible to develop a 

standardized voice, tailored for the user, for automated 

up- and down-link messages. Aviation personnel could 

be provided with user-selectable modes for information 

display (voice, text, graphics). Likewise, the industry 

could exploit vocoder technology to allow the user to 

recall information, and change the pitch, speech rate, 

and volume or display presentation.

4. Inability to make oneself understood may pose a 

threat to aviation safety as attention is diverted away 

from operational tasks and directed to listening to 

what is being said. During these times, more effort 

and concentration are needed to ensure the intent of 

the transmission is understood. This is especially true 

when confronted with an off-normal event such as a 

mechanical problem, passenger health issue, adverse 

weather, and so on. 

To mitigate these events, urgent and time critical message 

elements should be crafted as part of the DataCom message 

set. Users should have an area-based reference display for 

the phonetic pronunciation of native language numbers/

waypoints/NAVAIDS for routes and reroutes, as well as 

access to a universal thesaurus for DataCom message sets.

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