bluuebunny/crossref_metadata_2025 huggingface dataset:
Binaural speech enhancement by complex wavelet transform based on interaural level and argument differences
Authors: Hongo Satoshi , Suzuki Yôiti
Published: October 2013

Binaural information might enhance speech signals in noisy environments. Most precedent studies in this area have implemented signal processing in time and frequency domains. For this study, an enhancement method using complex wavelet transform (CWT) was proposed. The CWT has a scale domain whose bandwidth is inversely proportional to the scale level and may therefore be well compared to auditory filters. The proposed processing procedure is the following: (1) By computing CWT for a sound signal at every direction of arrival (DOA), a database (DB) of the scale domain wavelet coefficients is prepared for every DOA. (2) For binaural input signals from an unknown direction, the scale domain wavelet coefficients are calculated using CWT. (3) The DOA of the input signal is estimated as the direction for which interaural level and argument differences calculated from wavelet coefficients are the most similar to those in the DB. (4) The input signal is segregated similarly to FDBM (Nakashima et al., 2003) based on the estimated DOA. Experiments with a directional target signal and an interference sound source calculated from real HRTFs were conducted to show the effectiveness of the proposed algorithm. [This research was partially supported by Sendai Intelligent Knowledge Cluster.]
Study of the multimicrophone composed of unidirectional microphones for glasses-type hearing aids
Authors: Miura Kenzo , Arai Yasuhiko
Published: October 2013

That multiunit microphones (MUMs) using unidirectional units offer high sensitivity, low electronic noise, and low wind noise for the binaural hearing aids of glasses type is a fact that has already been reported. [K. Miura and Y. Arai, Th.2.D.4, 18th ICA, Kyoto, Japan (April, 2004)]. Two types of MUM are proposed herein for glasses-type hearing aids that have an array of three units positioned over the front frame for each channel. One type is the parallel front-direction array type (PA-MUM). The other type has a twisted direction array (TA-MUM). Performances of these MUMs were compared with that of a bigradient (BG) microphone positioned on the side frame. Results show that the PA-MUM has very narrow directivity; TA-MUM showed moderate directivity. The electronic noise and the wind noise of these MUMs were at a very low level. On the other hand, the BG microphone showed rather sharp directivity, but the electronic noise from the signal conditioner and the wind noise were both of a high level. These results show that PA-MUM is suitable for listening to speech in very noisy environments and that TA-MUM is suitable for general use for glasses-type hearing aids.
A model of own-voice perception with hearing aid usage
Authors: Stenfelt Stefan , Reinfeldt Sabine
Published: October 2013

Until recently, own-voice issues for hearing aid users were dominated by the occlusion effect. However, with the so-called open fittings, the occlusion-related own-voice problems have been significantly reduced. There are groups of hearing-aid users, though, for whom open fittings are unavailable, either because of high-frequency gain requirements or because of ear geometry. Of even bigger importance is the fact that hearing-aid users still have own voice issues, even when their occlusion problems have essentially been solved. A model is presented for perception of the own voice comprising an estimation of the own voice transmission by airborne and structure borne sound. Parameters of the model are the occlusion effect from the ear mould and ventilation tubes, gain settings of the hearing aid, and transmission properties of the middle ear during vocalization. The results show that both the airborne and structure borne sound transmission depend on both amplifier and acoustical parameters. A ventilation tube in the ear-mould may introduce a resonance that causes extreme alterations of the own voice spectral content. Although the model is far from complete, it can provide useful insights on own-voice related issues and give design directions to alleviate, at least partly, own-voice problems related to hearing aid usage.
Results from the National Institute for Occupational Safety and Health Administration/Environmental Protection Agency (NIOSH/EPA) interlaboratory comparison of American National Standards Institute (ANSI) S12.6-1997 Methods A and B
Authors: Murphy William J. , Berger Elliott , Gauger Dan , Witt Brad , McKinley Rich , Gerges Samir , Ahroon William
Published: October 2013

The Environmental Protection Agency and the National Institute for Occupational Safety and Health sponsored the completion of an interlaboratory study (E-A-RCalSM Laboratory, Howard Leight Industries, Brazil Acoustics and Vibration Laboratory, NIOSH Robert Taft Laboratories, US Air Force Research Laboratory, and US Army Aeromedical Research Laboratory) to compare two fitting protocols described in ANSI S12.6-1997 (R2002). Method A (informed user fit) and Method B (naive subject fit) were implemented according to the standard. Six models of hearing protection were tested in the study: two earmuffs, foam, premolded, and custom-molded earplugs, and canal caps. The muffs were counterbalanced both in testing order and the occluded and unoccluded conditions. The earplugs were counterbalanced across testing order and occlusion. Each laboratory tested 24 subjects for both methods and each protector. This paper reports on the results from this study. Particularly, the comparison of the statistical errors for each method and protector will be evaluated. In general the lower, 80th percentile, estimates of the expected protection were quite similar. The upper, 20th percentile, tended to exhibit effects that were dependent upon the method and the laboratory. [Work supported by EPA interagency agreement DW75921973-01-0.]
Has the Occupational Safety and Health Administration record-keeping rule changed hearing loss prevention programs?
Authors: Wells Laurie
Published: October 2013

The Occupational Safety and Health Administration (OSHA) record-keeping rule 29 CFR part 1904.10, changed the definition of recordable hearing loss and created a separate column on the OSHA 300 form to record noise-induced hearing loss (NIHL). In an effort to identify possible effects of the record-keeping rule change, an informal written survey was distributed at the National Hearing Conservation Association (NHCA) annual conference in February, 2006. NHCA conference attendees, because they specialize in hearing loss prevention, are likely to be familiar with hearing conservation issues so their perceptions are of particular interest. A total of 36 attendees, including audiologists, audiometric technicians (OHC), industrial hygienists (IH), mobile test company owners, occupational medicine physicians (OMP), and occupational health nurses (OHN) completed the ten-question survey. In summary, there appears to be a consensus that the everyday practice of hearing loss prevention has been affected by the record-keeping rule change, with both positive and negative influences. Employers seem to be paying more attention to HLPPs, which is, by itself, a positive outcome. Somewhat alarming however, is the finding suggesting that recordable STSs may be being ‘‘lined-out’’ or ‘‘denied’’ inappropriately in order to keep recordable rates artificially low.
Japanese young people’s recreational sound environment and hearing protection
Authors: Suzuki Yôiti , Saito Fumitaka
Published: October 2013

Intense sound may damage hearing even if the listeners are willing to listen to it. Risk of hearing disorders due to leisure time sound is an important problem in hearing conservation. A questionnaire survey of Japanese young people’s leisure time activities showed that in Japan concerts rather than discos seemed more influential and in comparison with the results in Finland, the awareness of the danger of intense sound was much less. The sound levels while listening to music with loudspeakers and at pop-music concerts were measured. While listening levels with loudspeakers were quite modest (avg.: LAeq=65 dB for favorite music pieces), at the two concerts the LAeq’s at audience positions ranged from 95 to 105 dB. Since the pop music performed at the concerts was mild relative to typical values in the present Japanese music scenes, this level may be regarded as near the minimum that could be expected for such activities. Additionally, LAeq while playing one of ten kinds of musical instruments at the player’s ear was measured. The results ranged from 76 (viola) to 110 dB (trombone). Consideration of hearing protection at music scenes and education regarding its value seem very important.
Variability in real-ear attenuation at threshold evaluations of hearing protection devices
Authors: Ahroon William A. , Hill Melinda E. , Lukas Kimberly B.
Published: October 2013

The American National Standard Method for the Measurement of the Real-Ear Attenuation of Hearing Protectors (ANSI S12.6-1997 [R2002]) contains explicit requirements for the physical parameters of the test facility used in measuring the performance of hearing protection devices and in subject selection and device fitting. However, the standard curiously does not provide a similar level of detail when considering the psychophysical procedure used to define ‘‘threshold’’ other than when an automatic recording audiometer is used. Most facilities conducting ANSI-based measurements of hearing protector performance appear to use a Bekesy tracking procedure, but other methods such as a modified method of limits or a method of adjustment procedure are implemented as well by some facilities. Following several tests of hearing protection over the past year, several examples of large variability caused by very low attenuation results in one or both runs in a few subjects have been noted. The data from these unusual subjects are analyzed and presented along with recommendations for the psychophysical procedures to be included in future versions of the standard.
Comparison of passive versus active noise reduction headsets in light aircraft cockpit noise: Communications intelligibility and workload
Authors: Casali John , Valimont Brian , Lancaster Jeffrey , Gauger Dan
Published: October 2013

Under instrument flight rules (IFR) conditions in Cessna 172R (95 dBA) cockpit noise, eight IFR-licensed pilots flew four 3.5-h nonstop flights in an FAA-certified, single-engine flight simulator, while wearing one of four communications headsets in each flight. All flights imposed an equivalently high level of air traffic control communications, at three Speech Transmission Index (STI) values: 0.30, 0.50, and 0.70. Perceptual and psychomotor workload were also controlled. In addition to a battery of flight-related metrics (some reported elsewhere), an objective, flight-embedded measure of communications intelligibility was obtained—the number of readbacks required of the pilot to attain 100% intelligibility on each command. An ANOVA revealed that as a group, the ANR headsets (Sennheiser HMEC300, Bose Aviation X, LightSPEED Thirty3G) required significantly fewer readbacks (averaging 1.2–1.3) than did the passive David Clark H-10-13.4 (averaging 1.5). Flight control performance, as reflected by deviations in assigned magnetic heading, altitude, and airspeed, was highest during flights with the Bose headset. Pilots’ workload estimates were measured using the modified Cooper-Harper scale, with 1 representing lowest workload and 9 representing highest. The three ANR headsets were associated with average workload ratings of 3.4–3.5, while the passive headset yielded a higher average workload of 4.4.
An evaluation of the acoustic properties of an improved combat arms earplug
Authors: Binseel Mary S. , Letowski Tomasz R.
Published: October 2013

This study investigates the performance of an improved version of the combat arms earplug (CAE). U.S. Army soldiers must operate in environments which can go from quiet to noisy in a moment. They also operate in environments where the predominant noise hazard can be either continuous or impulse noise. The current earplug of choice to address these varying protection needs is the CAE. The CAE is a two-sided earplug which provides linear attenuation for steady-state noise exposure on one side and nonlinear protection for impulse noise protection on the other. Although feedback from the field has been favorable regarding the functioning of the CAE, other concerns such as fit, comfort, size, and the need to remove, turn, and reinsert the earplug to change the modality have been raised. In order to address these concerns, the Army Research Laboratory provided funding for the development of an improved CAE. The improved CAE was evaluated for attenuation of continuous and impulse noise, soldier performance in localization and speech intelligibility tasks, and soldier acceptance on issues such as ease of use, perceived protection, equipment compatibility, sizing, and comfort. Results of these experiments will be discussed.
Design of linear time-domain filters for hearing protector modeling
Authors: Vipperman Jeffrey S. , Murphy William J.
Published: October 2013

Accurately modeling hearing protectors for predicting the hazard underneath them is of interest to many. This project modeled the single transfer path through the hearing protector from the free field to the ear drum, as an extension to the frequency-domain modeling method presented by Price and Kalb [J. Acoust. Soc. Am. 103, 2878 (1998)]. First, the real ear attenuation at threshold (REAT) data from the hearing protectors (muff and plugs) were converted to linear quantities and curve fit to form a continuous function of frequency, while preserving the low-pass characteristic. The resulting magnitude was combined with the head-related transfer function (HRTF) to form the magnitude of the total transfer function. Using complex cepstrum, a stable, complex frequency response function (FRF) was created by assuming a minimum phase transfer path. System identification methods were used to fit the FRF data to a parametric model that was converted to an infinite impulse response (IIR) digital filter. Subject-fit REAT data were used in order to represent real-world usage. Imperfect usage was modeled by derating the subject fit data by 1 standard deviation (SD). Tests on an artificial head are conducted to evaluate the filters in the time and frequency domains. [This research was supported wholly by NIOSH.]
Applicability of impulse noise hearing damage risk criteria (DRCs) to hearing protectors
Authors: Zera Jan , Mlynski Rafal
Published: October 2013

Hearing damage risk criteria, DRC, concerning exposure to impulse noise, developed by CHABA [Ward CHABA Report (1968)], Pfander [J. Acoust. Soc. Am. 67, 628–633 (1980)], Smoorenburg [New Perspectives on Noise] (Raven, New York, 1982), pp. 471–490], and Dancer [Acust. Acta Acust. 3, 539–547 (1995)], have been destined for impulses encountered in open space, in free-field conditions. To adapt these criteria for conditions in which hearing protective devices (HPDs) are used, a standard procedure was proposed in the literature (e.g., by Pfander) that consists in subtracting the attenuation of the HPD, typically 25 dB, from the impulse’s peak SPL. Such a simple method does not take into account the change of the signal waveform under the HPD, usually resulting in increased A, C, or D duration. In this study, the subtraction method was verified by a comparison of impulse noise DRC with the parameters of acoustic impulses measured under the earmuff: peak SPL, rise time, and A, C, and D duration. Results show that the subtraction method underestimates the possible hearing damage risk posed by exposure to impulse noise when a hearing protector is used. [Work supported by the Polish Ministry of Science and Education, Grants T07B00428 and SP03.1].
Criteria levels for nonoccupational noise exposure
Authors: Blomberg Leslie
Published: October 2013

Selecting criteria levels for nonoccupational noise exposure requires consideration of several factors. These include: (1) the need to protect public health and safety; (2) the diverse sources of nonoccupational noise exposure; (3) the inconsistent patterns of exposure, for example, the potential for multiple exposures in 1 day, or none; (4) complications caused by workplace exposure; (5) the fact that those exposed include children and minors; (6) the inability of the general public, without training or equipment, to understand traditional means of expressing noise exposure; (7) difficulties educating the public about nonoccupational noise; and (8) complications that may arise if levels are mandated or adopted by government bodies. Given these considerations, the paper argues there are actually three criteria levels needed: (1) one that delimits safe noise exposure; (2) one that reflects increased levels of risk and the need for increased vigilance in protecting hearing; and (3) one that indicates unsafe exposure, for which hearing conservation should be practiced. Moreover, new and simpler ways of determining these levels are needed. Specific levels are recommended, and a method developed by the Noise Pollution Clearinghouse for use by the general public to determine if a sound is too loud is presented.
Review of literature on hearing damage by personal stereo
Authors: Hammersho/i Dorte , Ordoñez Rodrigo
Published: October 2013

In the 1980s and 1990s there was a general concern for the high levels that personal stereo systems were capable of producing. At that time no standardized method for the determination of exposure levels existed, which could have contributed to overly conservative conclusions. With the publication of ISO 11904-1:2002 and 11904-2:2004, previous studies can be viewed in a different light, and the results point, in our opinion, at levels and listening habits that are of hazard to the hearing. The present paper will review previous studies that may shed light over the levels and habits of contemporary personal stereo systems, which can produce even higher levels and are of even wider use.
Molecular dynamics study on the nucleation and growth of cavitation bubbles
Authors: Takagi Shu , Tsuda Shinichi
Published: October 2013

Molecular dynamics simulations have been conducted for the nucleation and growth processes of cavitation bubbles in a decompressed liquid. To investigate the effects of noncondensable gas, the comparison between one-component liquid argon and two-component liquid argon, which includes helium gas molecules as impurities, was made. As a result, we observed that a competing coarsening similar to Ostwald ripening occurs in the one-component liquid argon, while coalescence of bubble nuclei frequently occurs in the two-component case. In spite of the different growth patterns between the two cases, the values of the growth exponent are close to 1/2 in both cases. However, it has been found that the scaling components that constitute the growth exponent, i.e., the scaling exponent for the total radius of all nuclei and that for the number of nuclei, are different between the two cases. These scaling components are discussed in relation to a driving force for bubble nuclei to grow. In addition, the asymptotic behavior of the size distribution function of bubble nuclei is also discussed using these scaling parameters.
Experimental analysis of blackbody emission from sonoluminescence in sulfuric acid
Authors: Hopkins Stephen D. , Camara Carlos G. , Putterman Seth J.
Published: October 2013

The spectrum of emission from a single xenon bubble in concentrated sulfuric acid driven at 30 kHz is an excellent fit to Planck’s law with a surface temperature of 8000 K. The measured flash width and emission radius are also consistent with blackbody emission. In this study the only fitting parameter available is the temperature [Phys. Rev. Lett. 95, (2005)]. [Research funded by DARPA.]
Drop tube generates 10-W flashes of sonoluminescence
Authors: Kappus Brian A. , Chakravarty Avic , Putterman Seth J.
Published: October 2013

Use of a low vapor pressure liquid such as phosphoric acid, with dissolved xenon in a vertically exited tube, generates ∼200-ns flashes of sonoluminescence with a peak power of 10 W. We are in the process of characterizing the bubble motion by use of backlighting, stroboscopic, and streak photography. We will also broach the topic of disequilibrium between atom and electron temperatures. [Research funded by DARPA. We thank Carlos Camara and Shahzad Khalid for valuable discussions.] a)Deceased.
Optical observation of collapses of two bubbles adhered to the quartz wall under ultrasound irradiation with high-speed video camera: Micro-jet arising from two collapsing bubbles
Authors: Yoshida Kenji , Nakatani Shintaro , Watanabe Yoshiaki
Published: October 2013

The mechanical action of a micro-jet, which arises from the collapse of bubbles, has been widely used for ultrasonic cleaning and sonoporation in medical field. The generation mechanism of a micro-jet induced by the ultrasound irradiation is focused on. In previous theoretical and experimental researches, the generation mechanism is well known when a single bubble is adhered to a rigid wall. However, its mechanism is not understood in detail when multiple bubbles exist on rigid wall. The optical observation of multi-bubble collapse greatly contributes to the development of micro-jet applications. It was observed that the collapses of two bubbles adhered to the quartz wall in an ultrasound field with high speed video camera (HPV-1, SHIMADZU). Maximum recording rate of this high speed video camera is 1000000 frames/second. The emitted ultrasound frequency is 27 kHz. From the observation, one of two bubbles was deformed after these bubbles vibrate. The micro-jet was generated to the opposite side against the deformed bubble when the deformed one touches the other. Then, the direction of the micro-jet to the quartz wall was almost horizontal. The number of micro-jets increased every time the distorted bubble touched the other. Finally, five micro-jets to the various directions were observed at the same instant.
Speech perception: Development from general mechanisms to modules
Authors: Kuhl Patricia K.
Published: October 2013

Are the mechanisms subserving speech perception modular or general process in nature? I will adopt a developmental perspective to address this question. Using data from cross-cultural, cross-species, and developmental experiments, I will argue that, early in infancy, the mechanisms underlying speech perception are domain general and rely on processing that is not exclusive to speech signals. Language evolved to capitalize on general mechanisms of perception and action, and this ensures that all infants, regardless of the culture in which they are born, initially respond to and learn from exposure to language. As experience with language ensues, neural commitment to the properties of the language to which an infant is exposed results in dedicated neural networks and speech perception becomes more specialized. Finally, I will suggest that adult members of the culture help instill language in the child by adjusting the language they use when addressing infants and children (motherese), a speech style that exhibits interesting acoustic properties. Language input to the child enhances its learnability. A model of the developmental process will be described. [Research supported by NSF and NIH.]
Music and language in deaf children with cochlear implants
Authors: Nakata Takayuki , Trehub Sandra E. , Kanda Yukihiko , Takahashi Haruo
Published: October 2013

Congenitally deaf children with cochlear implants successfully perceive speech in quiet environments, and many produce intelligible speech with normal voice quality. Because implants were designed to optimize speech rather than music perception, timing cues are preserved at the expense of pitch cues. Consequently, adult implant users tend to discontinue musical activities that were enjoyable prior to the onset of deafness. By contrast, congenitally deaf children enjoy a variety of musical activities including listening, singing, and playing instruments. Research in our laboratory suggests that musical activities may enhance child implant users’ speech perception skills. For example, initiation of music listening at home by children with cochlear implants predicted their success on a word recognition task. Moreover, earlier ages of implantation were positively associated with enhanced motivation for listening to music. In addition, child implant users were able to identify musical themes that accompanied their favorite television programs. Unlike hearing children, however, they could not recognize the music from the melody (i.e., pitch patterning) alone. Analyses of these children’s singing revealed rhythmic patterning similar to that of hearing children but pitch patterning that was grossly distorted. In short, rhythm plays a central role in child implant users’ musical experience.
The effects of musical experience on linguistic pitch perception: A comparison of Norwegian professional singers and instrumentalists
Authors: Ro/ Maren Helene , Behne Dawn , Wang Yue
Published: October 2013

Speech prosody and music share tonal attributes well suited for studying cross-domain transfer effects. The present study investigates whether the specific pitch experience acquired by professional singers and instrumentalists transfers to the perception of corresponding prosodic elements in a native and non-native language. Norwegian and Mandarin words with tonal distinctions, together with corresponding hummed tones, were presented dichotically in a forced attention listening test to three groups of native Norwegian listeners: professional singers, professional instrumentalists, and nonmusicians. While instrumentalists and singers were both more accurate (higher percent correct for both ears) than nonmusicians for Mandarin linguistic and hummed tones, only instrumentalists showed positive transfer to corresponding native Norwegian stimuli. Results indicate a pattern of perceiving tonal distinctions that mirrors the pitch experience acquired through professional vocal and instrumental training: Instrumentalists generally appear to rely on an autonomous, categorical pitch strategy, consistent with their primary training with discrete, fixed intervals. Singers, on the other hand, tend to use a similar strategy for nonlinguistic pitch perception, but not in processing native tonal contrasts. Overall, pitch experience acquired through musical training appears to have a positive transfer to non-native speech perception.
Effects of training with sentences at varied speaking rates on native English speakers’ perception of Japanese vowel length
Authors: Hirata Yukari , Cullings Emily , Whitehurst Elizabeth , Whiton Jacob , Lambacher Stephen G.
Published: October 2013

In training non-native speakers to perceive difficult second language (L2) phonetic contrasts, providing variation in speakers and phonetic contexts helps the formation of L2 categories [Pisoni and Lively, in Speech Perception and Linguistic Experience (1995), pp. 433–459. The present study tested the hypothesis that high stimulus variability in speaking rate would have positive effects for L2 learners. Native English speakers’ ability to identify Japanese vowel length was examined with three types of training: slow-only, fast-only, and slow-fast. Their perceptual abilities were measured with a pretest and posttest and compared with a control group that was not trained. Test stimuli were sentences containing Japanese disyllables spoken at three rates (slow, normal, fast). Participants were trained to identify the length of the second vowel of disyllables embedded in a sentence and they received immediate feedback. The pretest to posttest improvement of the slow-only (8.2%) and slow-fast (8.7%) training groups was significantly greater than the control group’s improvement (3.9%). However, the fast-only (7.7%) training group’s improvement did not significantly differ from the control group’s improvement. In addition, slow-fast training, unlike other training, had an advantage in performance on the fast rate stimuli. Implications for the variability theory will be discussed. [ Work supported by NSF Grant No. BCS0418246.]
An analysis of the factors reading rate, vocabulary ability, and speaking proficiency in relation to the test of English for international communication (TOEIC) scores of Japanese learners of English
Authors: Asano Keiko , Mochizuki Sudo Michiko
Published: October 2013

This study investigated the relationships between the TOEIC scores and the two factors of the reading rates and vocabulary abilities of Japanese learners of English. Also studied are the relationships between the scores of the two TOEIC sections and the learners’ speaking proficiencies. Applying the Rauding theory, which reported the same comprehension processes underlying reading and listening, to second language acquisition, this study tested the hypothesis that the processing time for reading had an effect on that for listening. The Japanese subjects in this study took TOEIC and standardized tests of reading rates and vocabulary abilities, and also participated in a production experiment. The results showed high correlations between the TOEIC scores and the two factors of reading rates and vocabulary abilities. They also showed the tendency that the improvement of reading rates and vocabulary abilities contributed to the improvement of not only the scores of the TOEIC Reading Section, but also those of the TOEIC Listening Section. In addition, this study clarified the degree to which the speaking proficiency measured by naturalness judgments of native speakers of English corresponded to the proficiency indirectly measured by the TOEIC Listening Section.
The long-term retention of phonetic categories by Japanese immersion graduates
Authors: Harada Tetsuo
Published: October 2013

English-speaking children in a Japanese immersion program, in which many content subjects are taught in Japanese, were reported to be successful in establishing phonetic categories for single and geminate stops in Japanese, although their categories deviated from those of Japanese monolinguals. However, it is unknown to what extent those children can retain their phonetic categories after they exit the program. Ten participants who had attended a Japanese immersion program in the United States from kindergarten or grade 1 to grade 5 and who were taking a university-level intermediate or advanced Japanese course at the time of data collection were recorded producing Japanese words including both singletons and geminates. Mean closure duration values were obtained, and the ratio of geminates to singletons for the immersion graduates was compared with that of English learners of Japanese having the same proficiency level in a regular Japanese program. The results show that the immersion graduates, who had been exposed to a substantial amount of Japanese at an early age, still retained the phonetic categories and could contrast singletons with geminates in Japanese, although their closure duration tended to be longer than the norm of monolingual Japanese speakers.
Development and validation of an automatic spoken Spanish test
Authors: Wilson Nicole , Rosenfeld Elizabeth , Bernstein Jared
Published: October 2013

The development and validation of a fully automatic computer-based test of spoken Spanish is described. The test takes between 15 and 20 min to complete and comprises readings, elicited imitations, opposites, short-answer questions, sentence constructions, and story retellings. The only response modality is spoken Spanish. Sets of vetted items were assembled into tests presented to over 1000 adult non-native Spanish learners and over 1000 native Spanish speakers from several countries. Expert human judgments of the non-native responses showed that the spoken response material carried sufficient information for highly reliable judgments of proficiency. In the development and validation process, over 60000 responses were transcribed and over 21000 human judgments were analyzed. The automatic scoring system is described. Its validation includes comparisons of machine scores with interactive human interviews and human ratings of speech recordings. Results suggest that machine scores have virtually the same information that is found in Oral Proficiency Interviews conducted by the U.S. Government raters or by official ACTFL interviews. Correlation between machine scores and combined interview scores (r=0.92) is higher than the interrater reliability of the professional interviewers themselves.
Factors influencing L2 vowel perception and production
Authors: Lopez Karece , Yu Yan Helen , Bell-Berti Fredericka
Published: October 2013

This study investigates relations among factors expected to influence vowel perception and production in second language learning, including AoA, LoR, L2 education (before coming to and in the US), and language use (in the US). Vowel production will be examined through phonetic transcription, listener identification, and acoustical analysis. Preliminary evidence indicates that, even though our participants arrived in the US after age 12, AoA is still of critical importance in second language learning. Furthermore, and as expected, LoR also contributes to L2 proficiency. AoA and LoR, however, do not account for the ability of all the participants to identify and produce the vowels of English; thus, we must also consider other factors, including L2 education and use. The hypothesis is that L2 educational background and language use influence L2 English speakers’ perception and production of English vowels.
Durational characteristics in production of English consonant sequences by Japanese speakers
Authors: Tanaka Kuniyoshi , Tajima Keiichi
Published: October 2013

Japanese has more limited consonant sequences (e.g., ‘‘honda,’’ ‘‘nissan’’) than English (e.g., ‘‘script’’). This difference becomes a problem for Japanese learners of English when they produce English words that contain consonant sequences. Japanese speakers often avoid these sequences by inserting epenthetic vowels between consonants or following word-final consonants (e.g., English ‘‘script’’ as /su.ku.ri.pu.to/). The present study examines how Japanese speakers produce consonant sequences in English and how speaking rate affects their productions. A group of native Japanese speakers and a control group of native English speakers read English words at normal and slow speaking rates. Segment durations in target consonant sequences were measured, and ratios of segment to word duration and segment to consonant sequence duration were calculated. Preliminary results suggest that the segment durations and ratios are clearly different between the two groups of speakers. For example, in /s/ + consonant sequences, Japanese speakers tend to produce a relatively shorter /s/ and a longer consonant compared to native English speakers. Also, the duration ratios do not seem to vary depending on the speaking rate for either group of speakers. Results will be discussed in terms of timing control in second-language learning. [Work supported by MEXT.]
Cross-language speech sounds: Differential sensitivity and L2 accent
Authors: Munro Miles
Published: October 2013

Individuals vary in their ability to perceive phonetic differences between speech sounds. Individuals also vary in their aptitude for acquiring accurate pronunciation of a second language. The research to be presented investigates a probable link between the two with the aim that capacity for phonetic perception may constitute a measure of second language aptitude. In a series of tasks manipulating memory and attention load, Native Mandarin speakers for whom English is a second language were tested on their ability to discriminate non-native speech contrasts that cluster around the Mandarin and English phonetic spaces with varying ‘‘distances.’’ Each contrast pair is phonemically meaningful in a significant portion of the world’s languages (UPSID 451). These scores were then related to measures of degree of accent in English. Related results examining working memory span will also be reported. Accordingly, an explanation of variability in later-learner L2 accent strength is explained as a consequence of idiosyncratic ability to perceive phonetic differences between speech sounds. This cognitive correlate’s account is consistent with the notion that a greater ability to perceive small differences between novel phones is crucial to their accurate acquisition and reproduction.
Performance of auditory search with Japanese speech by native speakers and its learners as L2
Authors: Asemi Noriaki , Hayashi Ryoko , Kakehi Kazuhiko
Published: October 2013

Auditory search experiments using normal Japanese speech (NJS) and time-reversed speech (TRS) [Asemi et al., Acoust. Sci. Technol., 24, 145–147 (2003)] demonstrated fast and accurate judgment of the presence or absence of the target NJS among distracting TRSs. For application of an auditory search to measurement of the ability of auditory comprehension of foreign language, the effects of the learning proficiency of Japanese on the speed and accuracy in the detection of the target NJS were examined through auditory search experiments for native and non-native speakers of Japanese. The experiment comprised two parts: an NJS was the target and TRSs were distractors and vice versa. Subjects were requested to judge the presence or absence of a target speech correctly and as quickly as possible when a target and several distracters were presented simultaneously and diotically. Results showed remarkable differences between the performance of natives and non-native speakers in error rates rather than in the reaction times. Moreover, significant correlations were found between the error rates and the learning experiences only when fewer than three utterances were presented simultaneously. [Work supported by MEXT.]
Neurophysiological basis of temporally cued phonetic contrasts in Japanese and American English listeners
Authors: Hisagi Miwako , Shafer Valerie , Sussman Elyse
Published: October 2013

The present study examined American English (AE) listeners’ perception of Japanese (JP) temporally cued contrasts of vowels and consonants. The mismatch negativity (MMN) component of event-related potentials (ERPs) was used as a measure to compare passive (visual-attention condition) and active (auditory-attention condition) discrimination in an oddball paradigm. JP nonsense temporally cued vowel ([tado] vs [taado]) and consonant contrasts ([mi■i] vs [mi■■i]) were presented to JP listeners, for whom the temporal cues are contrastive, and to AE listeners who have no knowledge of JP. The following results were obtained. (1) With respect to the type of contrast, MMNs were larger for vowel contrasts than consonant contrasts. (2) In the auditory-attention condition both groups showed a robust MMN to vowels. (3) In the visual-attention condition JP also showed a robust MMN, while AE showed a smaller amplitude or absent MMN. This group difference was significant for the vowel contrast. (4) Interestingly, in the auditory-attention condition, AE showed a larger late negativity at frontal sites for vowel contrasts than JP. The results support the hypothesis that first-language perception is an overlearned process that may interfere with second-language speech perception. [Work supported by NSF.]
Identification of English /r/ and /l/ in noise: The effects of baseline performance
Authors: Ueda Kazuo , Komaki Ryo , Adachi Takahiro
Published: October 2013

The effects of baseline performance on identification of English /r/ and /l/ in noise by Japanese listeners were examined. Japanese and American listeners’ perception of /r/ and /l/ was measured under various signal-to-noise ratios. Each Japanese listener’s baseline performance was also observed with an identification test with a large set of stimuli. Generally, the signal-to-noise ratio had a similar effect across Japanese listeners of different baseline performances, although the overall accuracy was dominated by the baseline. When 15 days of /r/-/l/ identification training in quiet were applied to a group of Japanese listeners, the training effect generalized to identification performance in noise. However, the performance of Japanese listeners did not reach the level that the native listeners exhibited. [Work supported by JSPS and 21st Century COE, Kyushu University.]
Effects of learners’ L2 proficiency and acoustic/semantic contexts of stimuli on the phoneme identification training
Authors: Ikuma Yuko , Akahane-Yamada Reiko
Published: October 2013

Former studies investigated that word recognition by L2 learners is affected by both acoustic and semantic contexts [Rothwell and Akahane-Yamada, J. Acout. Soc. Am. 112, 2386 (2002)]. It was also shown that these two context effects lead to different achievement in perception training [Ikuma and Akahane-Yamada, J. Acout. Soc. Am. 115, 2393 (2004)]. In this study, native speakers of Japanese were trained to identify English /r/ and /l/ within words or sentences. L2 proficiency level for each trainee was also measured by a short written test regarding vocabulary and grammar. Results showed that training with semantically contextual stimuli improved the identification accuracy for stimuli with semantically contextual cues, but not for stimuli without semantic cues. Furthermore, the L2 proficiency level correlated only with the improvement in identification accuracy of target phonemes embedded in the semantically contextual sentences. These results suggest that L2 learners tend to use semantic cues rather than difficult acoustic cues. However, semantic context may moderate the effect of auditory perception training. Thus, training with semantically neutral stimulus is necessary to improve perception ability even for high proficiency level learners. [Work supported by JSPS.]
Context really matters!—The influence of input types on L2 speakers’ perception of English liquids
Authors: Chen Sally , Fon Janice
Published: October 2013

This study aims to investigate how different input types can help improve the perception of language learners on L2 sounds. Twenty-four college students of a remedial English class are divided into three groups and are given audio inputs of different types. The first group listens to a wordlist, the second group to a story incorporating all the words on the wordlist, and the third group to a piece of classical music, serving as the control. The wordlist consists of 56 monosyllabic English words with word-initial liquids or liquid-containing clusters. Before the listening task, all three groups are given an online l/r perception test containing all the words on the wordlist (pretest). After the listening task, the same perception test is again administered, including the original 56 words and another 56 phonotactically matched pseudo-V words (posttest). Both accuracy and reaction time are measured for the two perception tests. Preliminary results showed that all participants had significantly higher accuracy and shorter RT for real words in the posttest. The story group showed the biggest improvement for both measures, followed by the wordlist group. The control showed the least improvement.
Categorization of a s
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l continuum in Japanese, Mandarin, and English
Authors: Nearey Terrance M. , Okamoto Aya , Zhang Chunling , Thomson Ron I.
Published: October 2013

A continuum of 168 synthetic sibilant+vowel stimuli was categorized by listeners of three languages (Japanese, Mandarin, and English). The contoid portion of each stimulus consisted of a 190-ms high-pass filtered white noise whose cutoff frequency varied from 1800 to 3800 Hz in 7 steps. (Signals were low-pass filtered at 8500 Hz before resampling to 22.05 kHz for playback.) Each (cascade formant) vocoid portion was 210 ms in duration varying in three F1 levels (from 300 to 430 Hz) crossed with four F2 levels (from 850 to 2100 Hz, with fixed F3 through F5). Each of the 84 noise+vocoid patterns was combined with two different F2 transition patterns, designed to slightly favor more alveolar or more palatal fricative responses. Appropriate response sets were determined in pilot studies for each language by native speakers on the research team. Corresponding software was designed to allow computer-controlled categorization. Data collection for 9 Japanese, 20 Mandarin, and 4 English listeners is complete (more is planned). Responses to the stimuli spanned at two or three sibilant and several (high-to-mid) vowel categories in each language. Possible effects of language-specific phonotactics on the response patterns will be discussed.
Learning of non-native tonal contrasts with or without tonal context
Authors: Ciocca Valter , Francis Alexander L. , Zhang Yanhong
Published: October 2013

The learning of non-native (Cantonese) tonal categories by native speakers of another tonal language (Mandarin) was investigated under two learning conditions. For listeners in the tonal context (TC) group, learning occurred by listening to target tones within various carrier phrases. Listeners in the no-context group (NC) were trained using target tones produced as single words. Training stimuli were produced by the same speakers for both groups. A high-variability procedure with feedback was used for training. Sixteen listeners (eight in each group) took part in eight sessions over a period of about 1 month. Categorical perception of Cantonese tones was measured before training (following a brief familiarization session) and after training. For both groups, tone perception was tested for one level- and one contour-tone continua using identification and discrimination procedures. Identification performance before and after training did not differ between the two groups for the level-tone continuum, showing evidence of learning of the (non-native) mid-level category. For the contour-tone continuum, the TC group showed better learning of the (non-native) low-rising/low-level contrast, as well as better perceptual distinction between low-rising and high-rising tones. [Work supported by Hong Kong RGC Grant HKU 7224/03H.]
Acoustic correlates of English lexical stress produced by native speakers of Mandarin Chinese
Authors: Zhang Yanhong , Francis Alexander L.
Published: October 2013

Native speakers of Mandarin Chinese have difficulty producing nativelike English stress contrasts. Acoustically, English lexical stress is multidimensional, involving manipulation of fundamental frequency (f0), duration, amplitude, and vowel quality. Errors in any or all of these correlates could result in poor realization of the stress contrast, but it is unknown which cues are most problematic for Mandarin speakers. Here we compared the use of these correlates in the production of lexical stress contrasts by 20 Mandarin and English speakers. Results showed that Mandarin speakers produced significantly less acceptable stress contrasts, although they did use all four acoustic correlates to distinguish stressed from unstressed syllables. Mandarin and English speakers’ use of amplitude and duration were comparable for both stressed and unstressed syllables, but Mandarin speakers signaled stressed syllables with a higher f0 than English speakers. There were also significant differences in formant patterns across groups, suggesting that Mandarin speakers were able to achieve appropriate vowel reduction in certain unstressed syllables, but not in others. Results suggest that Mandarin listeners’ production of lexical stress contrasts in English is influenced in part by native-language experience with Mandarin lexical tones, and in part by similarities and differences between Mandarin and English vowel inventories.