［研究ノート］

Sanno University Bulletin Vol. 37 No. 2 February 2017

Praat を使用した英語教授法：
通じやすい英語を話すための指導
Teaching English Prosody with Praat:
Aiming at Speaking Intelligible English

村松美映子
Mieko Muramatsu
Abstract
This paper investigates (1) how the best and the worst speeches judged by a native
English speaker were reflected in the pitch contours and sound waveforms; (2) how theseven male best (MB), the seven female best (FB), the seven male worst (MW), and theseven female worst (FW) speakers changed their speeches in the four-weekpronunciation practice with Praat; and (3) how the participants reacted to Praat. Foursentences from VOA were used. They were to read Sound (1) aloud as a pre-test. They
practiced it while viewing the pitch contours and sound waveforms. In the second lesson,
the typical examples of theirs and VOA were compared. These procedures werecontinued until the fifth lesson when they read Sound (1) as a post-test. Differences were
found between the best and the worst speakers in the pitch range, but not in the length.
The changes of the pitch range were statistically significant for FB and MW but not forMB and FW. No difference was found in length. Most participants became motivated tospeak English. This study suggests introducing Praat is useful, but further studies arenecessary to improve their speeches.

1. Introduction
It is well known that Japanese oral communicative skills in English are inadequate for sending
and receiving verbal information. Specifically, in Japanese English prosody, it has been pointed
out that common problems are narrow pitch ranges for utterances (Sugito, 1996; Okada, 2002;
Nariai and Tanaka, 2008; Sonobe, Ueda, and Yamane, 2009) and lengthened speech due to2016年9月2日

受理1

Praat を使用した英語教授法：通じやすい英語を話すための指導

insertion of vowels after consonants (Nishihara 2004; Katayama, 2010; Kamijo, 2013). Even if weknew that the appropriate English prosody was impor tant, what we did in most language
classrooms was mainly to read textbooks aloud (Taguchi, 2012) or teach through sentence
repetition after the teacher or audio recording (Arimoto, 2005; Iino & Yabuta, 2012). English isviewed as a Linga Franca in this globalized society, so it is essential for learners to acquire
intelligible English (Kouchiyama, Kadota, and Ootsu, 2004; Koizumi, 2007; Oka, Iino, Kanazawa,Tominaga, Chubachi and Nakamura, 2011). Thus, the introduction of a teaching methodology
which emphasizes prosodic features of English is an urgent necessity.
With the development of acoustic analysis technology, objective measures of Japanese English
prosody have been introduced, using software such as Praat, Sugi Speech Analyzer, Wavesurfer,
Speech Analyzer, Onsei Koubou Pro and the like (Sugito, 1996; Okada, 2002; Mori, 2006; Nariai,and Tanaka, 2008; Sonobe, Ueda, and Yamane, 2009). These backgrounds prompted me to show
my study’s participants the graphic analyses of a native speaker of English (NS) speech and topractice with them for an extended period. In this paper, I analyzed Japanese English with Praat.
Praat is software created by Paul Boerma and David Weenink from the University of Amsterdam.
The aim of this paper is to elucidate the following three points; (1) how the best and the worst
speeches judged by NS were reflected in the pitch contours and sound waveforms on the Praat
screen; (2) how seven male best speakers (MB), seven female best speakers (FB), seven maleworst speakers (MW), and seven female worst speakers (FW) changed their pitch ranges andlengths by practicing with Praat for four weeks; and (3) how the participants reacted to Praat.

2. The Study
2. 1 The Participants
Sixty-one sophomores (30 males and 31 females) with non-English majors from a private
university in Tokyo participated in this study.
2. 2 The Procedures
2. 2. 1 Selecting Sentences for Analysis
Four sentences were selected from the VOA English learning page. They include Sound (1)“These are common causes of accidental poisoning,” Sound (2) “The trial lasted for three days,”
Sound (3) “ ʻHotʼ is an easily understood word,” and Sound (4) “Many cities have interestingnicknames.”

2Sanno University Bulletin Vol. 37 No. 2 February 2017

2. 2. 2 Data Collection
Figure 1 shows the Data Collection Procedure.
Figure 1 Participantsʼ Procedure from the 1st to the 4th Lesson*Reviewing Period① Listen to TE and VOA② Look at the Pitch Contours and the Sound Waveform of TE and VOA and listen to theexplanation③ Repeat VOA↓Read Script (1), (2), (3),and (4) Aloud↓
Receive Sound (1), (2), (3), and (4)↓View and Edit Sound (1), (2), (3), and, (4) with Praat↓
Listen to the Explanation of Sound (1), (2), (3), and (4)↓Listen to and Practice Sound (1), (2), (3) and (4) with Praat Screen* These procedures were not carried out in the first week.
“TE” stands for typical examples.
In the first lesson, the Script of Sound (1) was given to the participants. Without practice, theparticipants were asked to read the script aloud and record their voices as a pre-test. I thencollected the recorded voices through a CALL system. Next, the Sound File (1) of VOA wasdistributed to them. They downloaded Praat, and were directed to draw the pitch contours andthe sound waveforms of Sound (1). I explained how to interpret them. Briefly, the pitch contour
shows highness and lowness of the voice, for instance, for “AME” in Japanese, HL for “AME”
means rain and LH for AME means candy. The higher the voice is, the more emphasized thesyllable is. The sound waveform illustrates strength and weakness of the sound: If the sound isloud and strong, the waveform becomes larger and intense. If the sound lasts longer, the sound3

Praat を使用した英語教授法：通じやすい英語を話すための指導

waveform lasts longer. Next, they were asked to listen to and practice Sound (1) while looking at
the pitch contours and the sound waveforms of VOA produced by Praat, so they were able toknow where to speak with a higher pitch, where to shorten their utterance, and the like. This
practice lasted for ten minutes.
Between the first and second lessons, I analyzed the pitch contours and the sound waveformsof the utterances of all participants collected from the first lesson using Praat. I picked up sometypical examples (TE) from all of the participant samples.
In the second lesson, in the reviewing period, the participants initially listened to Sound (1) ofTE and VOA. They looked at the pitch contours and the sound waveforms of TE and VOA andlistened to the explanation by me. They repeated the sound of VOA several times. Then withSound (2) in the second lesson, with Sound (3) in the third lesson, with Sound (4) in the fourthlesson, the same processes were carried out. In the fifth lesson, they were to read Script of Sound(1) as a post-test. Questionnaires were given.
2. 2. 3 Data Analysis
First, I asked NS from America to select MB, FB, MW, and FW (seven each ) from the datacollected in the first week. I call them “four groups” in this study.
The four values, which were maximum pitch, minimum pitch, pitch range, and length, of thepre-test and post-test of the four groups were calculated.

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Sanno University Bulletin Vol. 37 No. 2 February 2017

3. Results
Among 61 participants, three were absent from the fifth lesson’s recording session. Tworecordings were unusable due to mechanical errors. Thus, recordings from 56 participants (26males and 30 females) were used for analysis.
3. 1 Characteristics of the Four Groups in the First Week
Below are sample screens spoken by MB, FB, MW, and FW.
Figure 2 A Male Best Speaker (Pre-test)

Figure 3 A Female Best Speaker (Pre-test)5

Praat を使用した英語教授法：通じやすい英語を話すための指導

Figure 4 A Male Worst Speaker (Pre-test)

Figure 5 A Female Worst Speaker (Pre-test)

Comparing Figure 2 and Figure 3, and Figure 4 and Figure 5, roughly, the pitch contours by
MB and FB have more peaks and troughs than those by MW and FW. In the sound waveforms by
MW and FW, there were extended parts of each sound waveform. By listening to them, it was
found that these extended parts were caused typically by vowel insertion after consonant. They
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Sanno University Bulletin Vol. 37 No. 2 February 2017

pronounced like “kouzizu,” “obu,” and “poizoningu.” Also, I found lack of confidence in theirspeech.
Table 1 shows the four averages values in the first lesson among the four groups.
Table 1 The Four Average Values in the First Lesson among the Four Groups
Max.Pitch (Hz)Min. Pitch(Hz)PitchRange(Hz)Length(Sec)MB

162.81

94.88

67.94

3.27

FB

291.20131.19160.01

3.63

MW

126.09

95.05

29.02

3.83

FW

283.04175.10107.93

4.15“Max” stands for maximum pitch and “Min” stands for minimum pitch in the table.

The pitch range of MB was significantly wider than that of MW (t-test; p<0.05). The pitch rangeof FB was significantly wider than that of FW (t-test; p<0.05). The differences in lengths among
the four groups in the first lesson were not statistically significant.
3. 2 Changes of MB, FB, MW, and FW Over the Four-Week Lessons
Table 2 shows changes in the four average values from the first to the fifth week among thefour groups.
Table 2 Changes in the Four Average Values from the 1st to 5th Week among the Four Groups
1st Lesson
Max.
(Hz)

Min.
(Hz)

MB

162.81FB

5th Lesson

Range
(Hz)

Length
(Sec)

94.88

67.94

3.27

291.20131.19160.01MW

129.0995.05

FW283.04175.10Max.
(Hz)

Min(Hz)

Range
(Hz)

Length(Sec)

154.26

88.88

65.38

3.30

3.63

345.52111.81235.71

3.75

29.02

3.83

137.31

89.60

47.71

3.90

107.104.15

291.62184.94106.67

4.05“Max” stands for maximum pitch, “Min” stands for minimum pitch, and “Range” stands for pitch range in thetable.

The pitch ranges of FB and MW between the first and fifth lessons widened, and thedifferences were statistically significant (paired-t-test; p<0.05). The changes in pitch ranges of MB7

Praat を使用した英語教授法：通じやすい英語を話すための指導and FW between the first and fifth lessons were not statistically significant. The changes inlengths among MB, FB, MW, and FW between the first and fifth lessons were not statisticallysignificant.
3. 3 Questionnaire
Table 3 shows the results of the questionnaire.
Table 3 Checking understanding and confidence for the four weeks’ practiceStrongly
Agree

Neither
Agree nor
Disagree

Agree

Strongly
DisagreeDisagree(1) I understand what apitch contour is.

25

24

700(2) I understand what asound waveform is.

26

24

600

(3) Pitch contours arehelpful for practicing
pronunciation.

12211562(4) Sound waveforms arehelpful for practicing
pronunciation.

1424

1431(5) Praat is helpful forpractice.

1922753(6) I became more fluent
in English after thefour-week

624

15

92Questions were asking if they understand what the pitch contours and the sound waveforms
were, if the pitch contours and the sound waveforms were helpful for practicing pronunciationand so on. Thirty participants out of 56 answered they became fluent in English after the fourweek practice with Praat.

4. Discussion
4. 1 Characteristics of MB, FB, MW, and FW in the First Week
The original VOA Sound (1) was recorded by a male native speaker of English. Although the8Sanno University Bulletin Vol. 37 No. 2 February 2017

pitch ranges by MB were wider than those by MW, the pitch ranges of the two groups were far
narrower than that of NS. This confirmed conclusions from previous studies (Sugito, 1996;Okada, 2002; Nariai & Tanaka, 2008; Sonobe, Ueda, and Yamane, 2009)
That the differences in pitch ranges in the first lesson between MB and MW, and between FB
and FW were statistically significant (t-test; p<0.05) and the differences in lengths in the firstlesson among MB, MW, FB, and FW were not statistically significant suggested to us that the NSrater judged English with a wider pitch range as the best English and with a narrower pitch range
as the worst English: he relied upon the participantsʼ pitch ranges, but not on their utterance
lengths when judging whether the utterances were good or bad. In other words, NS
understanding of non-native English will partly depend upon pitch use.
4. 2 Changes of MB, FB, MW, and FW Over the Four-Week Lessons
As for the pitch ranges, the comparison between the first and fifth lessons between MB andMW, and between FB and FW left us with a question: Why did FB and MW widen their pitch
ranges, but not MB and FW?
In the 2.2.3 Data Analysis, I wanted to determine whether Praat is more beneficial for the best
speakers or the worst speakers. The results would hopefully provide a clue for determining more
appropriate candidate participants for this methodology. The results, however, were more
conflicting: FB and MW widened their pitch range, but MB and FW did not. Thus, it wassuggested that another research design is necessary for this issue, for example, by monitoring
how the participants of the best and the worst groups practice English with the Praat screen, orby conducting a longer study using this methodology.
As for the speech lengths, the four groups did not show differences between the first and fifth
lessons; in other words, visualized sounds did not help them adjust the lengths. It is difficult toinvestigate speech lengths. They were complicated because they depended on at least threeelements; (1) speed of reading the whole sentence; (2) fluent production without word-by-word
pronunciation; and (3) smooth pronunciation without inserting vowels after the consonants. Fromthe results obtained in this study, it is not clear yet if they were unsuccessful in avoiding inserting
vowels after consonants, or if they avoided inserting vowels to some extent, but other hindrance
lengthened their utterances. Further investigation will be necessar y to tr y to pin down thecauses. At the same time, other factors concerning the lengths of speech should be analyzed
thoroughly to improve them, because an utterance deemed as appropriate in length may havecontained post-consonant vowels or may have been pronounced word-by-word but spoken at a9

Praat を使用した英語教授法：通じやすい英語を話すための指導

very high speed.
4. 3 Questionnaire
I learned from the questionnaire that most par ticipants have positive attitudes towards
visualized sounds or Praat. In English education, especially in speaking, participantsʼ motivationand confidence are most important. Therefore, this methodology could be predicted to help
Japanese learners improve oral communicative skills over the long term.

5. Conclusion and Future studies
It is widely believed that it is impossible for young adult L2 learners to speak like nativespeakers. Now it is our job, as language instructors, to show attainable goals for L2 learners, forexample, widening the pitch ranges and avoiding vowel-insertion. In other words, since English
as a Linga Franca is widely acknowledged, we must present an English threshold that will beintelligible for both NS and non-native English speakers. In this study, I paid attention specificallyto improve prosody in reading aloud tasks. For future research, we must discover methods toenhance oral communicative skills in spontaneous speech based on this study, and to improveother elements of English prosody such as length.
Lastly, I recommend this methodology which introduces Praat, to language classrooms,
because this study showed: (1) By using this software, the participants quickly learned to widen
their pitch ranges; (2) The participants got used to Praat quite soon, started to enjoy applying iton their computers, and were motivated to learn with it; and (3) This software was free of charge,
easy to download and install, so anyone can use it, both inside and outside of the classroom. Praat
has a lot of potential if we use the formant, pulse, spectrogram and so on, which I did not use inthis experiment. This methodology, using Praat, is expected to create other new methodologies,
to enhance the whole oral communicative skills of Japanese learners of English in the future.
Part of this paper was presented at JACET KANTO 8th Annual convention, Aoyama Gakuin
University, Tokyo, 2014.

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Sanno University Bulletin Vol. 37 No. 2 February 2017

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