bluuebunny/crossref_metadata_2025 huggingface dataset:
A study on the modified urban soundscape of a city due to introduction of elevated structures.
Authors: Ramasamy Kalaiselvi , Alur Ramachandraiah
Published: October 2013

The urban soundscape of cities in a developing country like India are slightly varied by virtue of the fact that the composition of the traffic is heterogeneous accompanied by variance in road geometry and varying density of the buildings on the either side of the road and other community noise sources. Urban planning plays a vital role in organizing a city’s traffic flow. To avoid congestion of traffic streams introduction of flyovers in the traffic flow happens to be a common feature in many urban environments. Through introduction of flyovers an increase or decrease in environmental noise characteristics occurs. In this paper a noise mapping study has been attempted along with field measurements of L10, L50, L90, and Leq to understand the soundscape of the city due to such types of modified topography. It also describes how the local characteristics of the city and changed topography alters the soundscape of the city. The theoretical computation of noise levels has been carried out using the sound plan software. It is observed that a reasonable reduction of Leq occurs in the immediate vicinity of noise sensitive areas of significant buildings such as hospitals and educational campuses.
The acoustical status of U. S. national parks.
Authors: Fristrup Kurt
Published: October 2013

Acoustical monitoring data have been collected for more than 40 national park units, spanning a wide range of regions, resources, and park purposes and values. Comparative analyses of these data reveal the extent of noise pollution in national parks. Transportation noise is audible in many wilderness areas more than 30% of the daylight hours, with peak hourly levels approaching 70%. Peak levels from noise events can be more than 50 dB above the natural background under air tour routes, and between 10–20 dB above background for high altitude aircraft. Hourly Leq values can be as much as 6 dB above natural levels. These data also reveal the degree to which various noise metrics covary in these natural settings. This information helps inform selection of a compact set of metrics that can assess several functional impacts of noise while minimizing redundancy.
Spatial phase-inversion technique for parametric source with suppressed carrier.
Authors: Kamakura Tomoo , Nomura Hideyuki , Sakai Shinichi
Published: October 2013

Two planar projectors with the identical rectangular apertures are placed side by side. Both the projectors are radiating bifrequency ultrasound beams of finite amplitude in the air. The frequencies are 40 and 42 kHz but the initial phases are different. Especially, two extreme cases are considered: one is conventional in-phase driving, and the other is phase inversion driving. Sound pressure profiles were measured along and across the sound beam axis for the primary waves and the difference frequency wave of 2 kHz. The second and third harmonic components of the difference frequency were measured as well. Obviously, the pressure levels of the primary waves were suppressed considerably near the beam axis due to phase cancellation when the driving signals were out-of-phase by 180 degrees. The beam pattern of the difference frequency was, however, almost the same as the case where the signals were in phase. Interestingly, the pressure levels of the harmonics were reduced more than ten decibels. The validity of experimental results has been supported by good agreement with the theoretical predictions based on the Khokhlov-Zabolotskaya-Kuznetsov model equation. [Work supported by JSPS.]
Infrasound-convection nonlinear interaction.
Authors: Naugolnykh Konstantin
Published: October 2013

The temperature stratified atmospheric layer is unstable and convection flow can be developed in such an area. Convection happens because warm less dense air goes up while cooler air comes down. The presence of infrasound produces modulation of convection flow and the sound wave amplification. The process of infrasound-convection nonlinear interaction is considered in the present paper. The equations of a compressible fluid convection are derived, which is characterized by the modified Rayleigh number, in comparison to this number for the incompressible flow, and condition of infrasound amplification is obtained. The increment of infrasound amplification turned out to be proportional to the Rayleigh number.
Acoustic nonlinearity in fluorinert.
Authors: Pantea Cristian , Sinha Dipen N. , Osterhoudt Curtis F. , Mombourquette Paul C.
Published: October 2013

Fluorinert FC-43 nonlinearity was investigated using two approaches: (i) a finite amplitude method with harmonic production and (ii) a nonlinear frequency mixing in the fluid with consequent beam profile measurement of the difference frequency. The finite amplitude method provides information on the coefficient of nonlinearity, β, through the amplitudes of the fundamental and the second harmonic, at a certain transmitter-receiver distance. A calibrated hydrophone was used as a receiver in order to obtain direct pressure measurements of the acoustic waves in the fluid. The role of transmitter-receiver distance in β determination is investigated. In the second approach, a single transducer is used to provide two high-frequency beams. The collinear high-frequency beams mix nonlinearly in the fluid resulting in a difference frequency beam and higher order harmonics of the primaries. The difference frequency beam profile is investigated at lengths beyond the mixing distance. The experimental data are compared with the KZK theory.
Flow through orifices caused by large-amplitude asymmetric sound waves: Theory and experiment.
Authors: Westervelt Peter J.
Published: October 2013

When the displacement amplitude of an acoustic wave consisting of equal parts fundamental and second harmonic exceeds the diameter of a circular orifice, steady flow is generated whose direction is determined by the phase of th etwo wave components [P.J. Westervelt, Ph.D. thesis "The interaction of a finite amplitude acoustic wave with small obstacles and orifices," MIT, 1951)]. Some applications to semipermeable biological membranes are discussed. [Work supported by the Office of Naval Research].
Measures of wideband power reflectance in otosclerotic ears.
Authors: Wróblewski Marcin , Neuman Arlene C. , Jiang Nancy , Lalwani Anil K.
Published: October 2013

Wideband reflectance (WBR) is a new method of evaluating middle ear function. While several studies have reported WBR data obtained from persons with normal hearing and from children with otitis media, few data have been reported describing results typical of other types of middle ear pathology. The purpose of the present study was to collect data from a group of persons with clinically diagnosed otosclerosis and to compare the measures of WBR (including reactance, resistance, impedance magnitude, and transmittance) to measures obtained from persons with normal middle ear function. WBR data were collected from 17 preoperative and 18 postoperative otosclerotic ears as well as from 57 ears without middle ear pathology. Measures from four otosclerotic ears allowed for a direct comparison of pre- and postoperative middle ear function. There was a variety of responses from ears with otosclerosis. Preoperatively, while some otosclerotic ears showed a pattern reported in previous case studies (i.e., increased WBR below 1000 Hz indicating enlarged middle ear stiffness), others fell within the normal range. Postoperatively, some ears showed a pattern typical of an increased mass component of middle ear impedance (i.e., decreased WBR below 1000 Hz), while others fell within the normal range.
A comparison of gap-detection thresholds through audition and touch in listeners with real and simulated hearing impairment.
Authors: Reed Charlotte M. , Desloge Joseph G. , Perez Zachary D. , Delhorne Lorraine A. , Braida Louis D.
Published: October 2013

Gap-detection thresholds were measured in listeners with real and simulated hearing loss under conditions of auditory or tactile presentation. The audiometric thresholds of each of ten listeners with sensorineural hearing loss (21–69 years of age) were simulated in groups of age-matched normal-hearing listeners through a combination of spectrally shaped masking noise and multiband expansion. The leading and trailing markers for the gap-detection task were 250- and 400-Hz sinusoids with a nominal duration of 100 ms. Gap-detection thresholds for a nominal baseline gap of 0 ms were measured for four different combinations of leading and trailing markers (250–250, 250–400, 400–250, and 400–400 Hz) using a 3I, 2AFC procedure. Auditory measurements were obtained for monaural presentation over headphones using a marker level set to be equal to the maximum of 70 dB SPL or 10 dB SL. Tactile measurements were obtained using sinusoids presented to the left middle finger through an Alpha-M AV-6 vibrator at a level of 25 dB SL. Results are discussed in terms of (a) spectral-disparity effects of leading and trailing markers; (b) relation of thresholds for auditory versus tactile presentation; and (c) comparisons of results from listeners with real and simulated hearing loss. [Work supported by NIH-NIDCD R01 DC00117.]
The impacts of age and absolute threshold on binaural lateralization.
Authors: Gallun Frederick J. , Diedesch Anna , Engelking Erin
Published: October 2013

Listeners varying in audiometric thresholds (70-dB range) and in age (52-year range) lateralized complex tones relative to a diotic standard. Stimuli were composed of one, two, three, or six tones amplitude modulated at a rate of 75 Hz. Carrier frequencies were selected from a set of seven values (roughly log-spaced between 700 and 7000 Hz) and sensation levels were equated across listeners. Baseline performance was obtained for one- and two-component signals and the effects of diotic interference were assessed with two-, three-, and six-component signals. For all signals, the dichotic components contained interaural differences in time (whole-waveform delay), level, or both across a range of values. Listeners with higher audiometric thresholds performed more poorly in all conditions, despite the use of equivalent sensation levels. Diotic interferers reduced performance, but there were no additional impacts of age or absolute threshold. Statistical analyses indicated that the impacts of age were primarily due to the co-occurring increases in pure-tone thresholds, suggesting that: (1) absolute threshold is a better predictor of binaural ability than age and (2) reduced sensitivity to binaural differences is not addressed by presenting stimuli at equivalent sensation levels. [Work supported by VA RRD CDA-2 C4963W.]
Age-related differences in the time it takes to form auditory images of broadband noises.
Authors: Wang Mengyuan , Schneider Bruce , Wu Yanhong , Wu Xihong , Li Liang
Published: October 2013

When correlated noises are presented over earphones to the two ears, listeners typically form a fused compact image of the noise. However, when the noises presented to the two ears are independent, listeners tend to hear two noises: one on the left and the other on the right. In Experiment 1 we determined the minimum duration required to form auditory images by asking listeners to distinguish between a 1-s presentation of independent noises to the left and right ears, and another 1-s presentation in which the noise was correlated for x ms before switching to two independent noises. In Experiment 2, one of the noises was correlated throughout the 1-s presentation; the other started off uncorrelated before switching to correlated. Younger adults performed better than older adults in both experiments. However, the performance of younger adults was better in Experiment 2 than in Experiment 1, whereas the reverse was true for older adults. The implications of these results for age-related changes in auditory scene analysis will be discussed. [This work was supported by the National Natural Science Foundation of China, the Natural Sciences and Engineering Research Council of Canada, and the Canadian Institutes of Health Research.]
Analysis and prediction of underwater sound radiation from a cylindrical pile driven by an impact hammer.
Authors: Hastings Mardi C.
Published: October 2013

A vibroacoustic model for sound radiation from a submerged pile was developed to predict sound pressure levels generated during offshore construction activities. It was implemented in MATLAB and verified with measured data reported in the literature. The modal response of a cylindrical pile to hammer impact is first determined. Contributions from all dominant modes are then summed at various ranges to produce a two-dimensional spatial mapping of sound pressure level. The analysis was used to investigate the effects of pile material, size, and geometry on radiated sound pressure levels. Results indicate that smaller diameter piles of the same material do not necessarily produce lower sound pressure levels, but rather shift the peak sound pressure levels to higher frequencies. Because these basic parameters affect bandwidth as well as sound levels, there is no simple way to classify source level and frequency. Peak sound pressure levels generated underwater by driving steel piles with impact hammers into the sea bottom can easily exceed 200 dB re 1 μPa at a range of 10 m, so accurate prediction of the sound field is needed to assess potential risks to the environment.
How regional dialect effects second language learning.
Authors: Teng Mu-Ling , Ke Yi-Chu , Chen Chu-ting , Lu Bo-hong , Ip Lai-Iok , Pan Ho-hsien , Chen Shih-wen , Yu Hsiu-Min
Published: October 2013

This paper discussed dialect effects on L2 learning. Data from advanced English-learning students were separated into groups according to geographic regions: Northern, Middle, and Southern parts of Taiwan. Subjects were asked to read out loud eight English words, namely, “heed,” “hid,” “head,” “had,” “hod,” “hawed,” “hood,” and “who’d.” Acoustic information, such as F1 and F2, were measured; also, since Taiwanese English learners tend to use temporal cues to distinguish tense and lax vowels, duration of each word were also measured. Comparing the vowels read by the subjects with native speakers, we found that the Northern group had very similar patterns with native speakers in both spectral and temporal cues. As for the Middle group, the vowel shape was going upper right in the vowel chart and the duration pattern was quite distinctive from native speakers. Furthermore, all the subjects from the Southern part of Taiwan speak both Mandarin and Taiwan Min and their vowel spaces were the most deviated from native speakers, from which we assumed that PAM model (Best, 1993, 1995) could give a reasonable explanation: they have two vowel systems that could be referenced from, thus they might easily get confused. However, several problems still need further examination.
Identification and discrimination of tonal pitch in speech and nonspeech stimuli for Chinese- and English-native speakers.
Authors: Liu Chang
Published: October 2013

Given that Chinese is a tonal language while English is not, the present study is to examine how language background affects tonal identification and discrimination in speech and nonspeech signals for Mandarin-Chinese and American-English native speakers. The fundamental frequency (f0) contour was systematically manipulated from tone 2 (rising), to tone 1 (level), and to tone 4 (falling) for three types of signals: Chinese vowels /ɑ/, English vowels /æ/, and tonal sweeps. Both groups of listeners showed categorical perception in the identification of tones 1, 2, and 4, while Chinese-native speakers showed sharper boundaries across tonal categories than English-native speakers. Just-noticeable difference (JND) in tonal pitch was also measured for the standard tone 1, tone 2, and tone 4 of the three types of signals. JND was significantly smaller in speech stimuli for Chinese-native speakers than for English-native speakers, but quite comparable between the two groups of listeners for nonspeech stimuli. There results indicate that tonal pitch may be perceived specifically in speech stimuli, and for nonspeech stimuli, the capacity to process the tonal sweeps is similar across listeners with different language backgrounds.
Tonal confusion patterns in Mandarin by Cantonese listeners.
Authors: Tu Jung-yueh
Published: October 2013

It is well-attested that linguistic experience affects the perception of non-native sounds. The vast majority of research on L2 perception has been carried out on segmental features from the perspective of phonetic similarity between the L1 and L2 sound systems. The general goal of this study is to expand our understanding of cross-linguistic comparison in non-native speech perception, focusing on the somewhat understudied area of perceptual assimilation at a suprasegmental level. More specifically, it deals with comparisons of prosodic systems in two tone languages, Mandarin and Cantonese. The current study examined perception of Mandarin tones by Cantonese listeners. In Experiment 1, Mandarin tones were presented and the Cantonese listeners were requested to identify which tone they heard. In Experiment 2, the Cantonese listeners were instructed to rate how similar each Mandarin tone was to a Cantonese tone. Preliminary results suggest that tonal confusion errors may result from not only the similar acoustic properties of the tone pairs but also perceptual assimilation between L1 and L2 tonal contrasts. These findings are discussed in terms of the effects of L1 prosodic system on L2 perception and how perceptually assimilation patterns predict listeners’ perception performance at the domain of lexical tones.
Wavefront curvature and near-field corrections for scattering by targets buried under sea-floor ripple.
Authors: Lim Raymond , Sammelmann Gary S. , Lopes Joseph L.
Published: October 2013

Curvature of the incident field wavefront has been implicated in discrepancies between modeled and measured pressure fields scattered at shallow grazing angles from targets buried under ripple in NSWCPCD’s test pond, where the range to the target is limited to about 10 m. Improvements on our attempts to correct for these and other near-field effects in existing incident-plane-wave-based models is described here. Explicit numerical integration of incident field expansion coefficients as well as the basis functions needed to formulate the transition matrix solution for the scattering process is used in order to create a reliable benchmark for comparisons with simpler corrections and measured data. It is found that some care must be exercised in performing the required two-dimensional wave vector integrals because the ripple wave vector can cause integration to be unstable in the perturbative terms accounting for ripple effects. Results are compared with recent modifications of existing sonar simulations and data collected in NSWCPCD’s test pond. [Work supported by ONR and SERDP.]
Design and testing of a variable acoustics production studio with reflection free zone control room.
Authors: Mooney Jon , Harrison Seth , Brennan Jon
Published: October 2013

The new home of Curtis, Inc. in Cincinnati, OH, includes a recording studio and control room designed and tested by KJWW Engineering Consultants. The recording studio features adjustable wall treatments, which may be opened in varying degrees to adjust absorption and diffusion within the room. The adjoining control room has been designed to position the recording engineer inside a reflection free zone (RFZ). This design directs speaker reflections from the front of the room away from the recording engineer, extending the initial time delay (ITD) without requiring a dead front end. The control room also features unique wall and ceiling treatments, which serve not only as variable binary diffusers and absorbers but also as storage cabinets. These design elements allow for broad adjustment of the control room acoustics. The configurable design of the recording studio and control room coupled with exceptional sound isolation enable this facility to create flexible recording and listening environments. This paper will present an overview of: 1. The recording studio and control room designs; 2. The changes required during construction and their effects; 3. Acoustical measurements, quantifying the variable response of the rooms; 4. Operation of the rooms and preferred settings.
Processing acoustic features of animal vocalizations using classification procedures.
Authors: Hanser Sean F. , McCowan Brenda , Doyle Laurance R. , Bowles Ann E.
Published: October 2013

Remote methods for classifying age, sex, group membership, or individual identification of animals that live in visually obscured environments are extremely valuable tools for field biologists, but reliable identification of individual callers still presents important challenges. Acoustic features of animal vocalizations can be processed to extract caller identification using a variety of sophisticated classification techniques, but the exact classification process can be difficult to justify rigorously and challenging to repeat on novel data. A feature extraction and classification process that is clear, simple, and repeatable would be a major benefit to wildlife studies. Classification and regression trees (CART) generate intuitive and clear processes for handling multidimensional acoustic information. Examples of CART applied to Mexican spotted owl (Strix occidentalus lucida) and humpback whale (Megaptera novaeangliae) vocalizations will be provided. These CART results will be compared to other classification techniques, particularly neural networks. CART performance was comparable, but had the advantage that it yielded explicit classifiers used to categorize vocalizations, making it easy to integrate into acoustic surveying systems. This promises to be a valuable tool for conservation and management of these and other endangered species.
Ultrasound-guided high intensity focused ultrasound therapy—Safety concerns from a clinical perspective.
Authors: ter Haar G. R.
Published: October 2013

The use of high intensity focused ultrasound (HIFU) in surgical applications has continued to grow at a rapid pace. Nevertheless, safety concerns limit the adoption of ultrasound guidance due to the persistent lack of real-time monitoring and quantitative measures of clinical endpoints. Imaging and temperature estimation using magnetic resonance remains the preferred approach for guidance and monitoring in much of the Western world, while ultrasound imaging has seen wide use in China. Recent reviews of clinical outcomes have raised new regulatory concerns in China and are likely to increase scrutiny elsewhere. Still lacking are near real-time measures of in situ parameters such as acoustic power, heating rate, or temperature, from which clinical endpoint metrics may be obtained with acceptable accuracy. Furthermore, therapy planning remains a semiquantitative process, producing highly variable results, particularly in the absence of feedback. This presentation provides an update on the clinical impact of insufficient quantification of ultrasound-guided HIFU therapy.
Analysis of pile driver exhaust and impact noise.
Authors: Zechmann Edward , Hayden Charles
Published: October 2013

In July 2008, NIOSH accomplished a preliminary noise survey focused on gathering impulsive noise data from pile drivers. The purpose of the noise survey was to better understand the noise characteristics of pile drivers. NIOSH gathered time record data of H-beam piles being driven into hard rock. This data was used to characterize the frequency content of the major impulsive events (impact and exhaust cycles). Knowing the frequency content is necessary to apply existing or develop new noise controls, since many noise controls are frequency dependent. Gathering the frequency content of a pile driver’s impulsive noise signal is typically difficult using off-the-shelf measurement and analysis equipment and software. Reliable time record data is necessary to confidently extract the frequency content from the signal. NIOSH has developed an Impulsive Noise Meter laptop program to properly gather and analyze these impulsive signals. By analyzing the third octave band peak levels of each impact and exhaust cycle of the pile driver operation, the frequency dependence was determined. Results of this analysis showed the frequency content varied as the pile was driven further into the ground. This implies that broad spectrum noise controls are necessary to control those noise emissions.
Are hybrid cars too quiet?
Authors: Robart Ryan L. , Rosenblum Lawrence D.
Published: October 2013

The increase in availability of alternative fuel vehicles has elicited concerns for pedestrians who might not hear the approach of these quieter cars. Three experiments tested the relative audibility of hybrid vehicles (in their electric mode) and internal combustion engine (ICE) cars. Binaural recordings were made of the cars approaching from either the right or left, at 5 mph. Subjects were asked to listen to these recordings over headphones and press one of two buttons indicating from which direction the car approached. Subjects’ accuracies and reaction times were measured. The first experiment revealed that (sighted) subjects were able to determine the approach direction of the ICE cars substantially sooner than the hybrid cars. A second experiment added the natural background sounds of idling engines to the stimuli. The addition of background sound disproportionately hindered perception of the hybrid cars, so that they could not be localized until very close. A final experiment testing both sets of stimuli with blind subjects revealed the same pattern of results. Implications of these results for pedestrian safety will be discussed. [Work supported by a grant from the National Federation for the Blind.]
Quenching of bandgaps by flow noise.
Authors: Sanchez-Dehesa Jose , Elnady Tamer , Elsabbagh Adel , Akl Wael , Mohamady Osama , Garcia-Chocano Victor , Torrent Daniel , Cervera Francisco
Published: October 2013

We report an experimental study of acoustic effects produced by wind impinging on noise barriers based on two-dimensional sonic crystals with square symmetry. We found that the attenuation strength of sonic-crystal-bandgaps decreases for increasing values of low speed. A quenching of the acoustic bandgap appears at a certain speed value that depends of the barrier filling ratio. For increasing values of low speed, the data indicate that the barrier becomes in a sound source because of its interaction with the wind. We conclude that flow noise has paramount importance in designing acoustic barriers based on sonic crystals. [Work supported by Spanish AECI.]
Measurement of acoustic wave frequency by Bragg light diffraction.
Authors: Akhmedzhanov R. Farkhad
Published: October 2013

The new technology is offered for measurement of acoustic wave frequency. The method is based on using the Bragg light diffraction on the hypersonic transversal acoustic wave in a gyrotropic crystal. As is well known, the intensity of diffracted light in this case is strongly dependent from the quantity of specific rotation of polarization vector. As a result, using the standard calibration of light intensity it is possible to measure the changes of acoustic wave frequency. Measurements of the diffracted light intensity have been carried out in several points along the direction of the acoustic wave propagation. The applied sample of LiNbO3 was oriented along the crystallographic axis of the third order with the accuracy of 10′. The plane-polarized transverse acoustic waves were excited in the frequency range from 900 MHz to 1.2 GHz. The results obtained at the average frequency 1.0 GHz were shown, that the intensity of diffracted light intensity is sensitive parameter to the change of the transverse acoustic wave frequency. The dependence of the diffracted light intensity from the quantity of specific rotation frequency was used for determination of the acoustic wave frequency by the appropriate model equation accurate within 0.1%.
High-frequency acoustic properties of water-saturated sediments: Laboratory study.
Authors: Sessarego Jean-Pierre , Guillermin Rgine , Ivakin Anatoly N
Published: October 2013

This study was performed in controlled laboratory conditions using several broadband transducers to cover a wide frequency range from 200 kHz to 3MHz. Various types of sediments were used: natural medium and coarse sand, and glass beads with corresponding mean sizes. Sound speed and attenuation were measured and compared with predictions of Biot theory. The theory failed to predict both high attenuation and negative dispersion of sound speed observed at very high frequencies (above 500 kHz for medium sands), which can be assumed an effect of strong grain scattering. All the measurements were performed at different times to ensure the repeatability of the results. A comparison of results obtained for natural sands with those for artificial sediment (glass beads) of the same mean size, allowed observing the influence of the grain shape on the reflected and backscattered signals. Also, the influence of the transducer directivity diagram on the sediment reflectivity was observed. This effect is discussed and shown to be essential in the case of strong incoherent scattering observed for coarse sediments. Finally, the time-frequency contents of the reflected signal were analyzed. It was found to be very sensitive to the granular structure of the sediment. [Work supported by CNRS and ONR.]
Acoustic correlates of Tone 3 and Tone 4 in Mandarin.
Authors: Yeh Chia-Hsin
Published: October 2013

Perceptual similarity between Tone 2 and Tone 3 in Mandarin was widely discussed in previous studies [Moore and Jongman (1997), Huang (2004), Bent (2005)]. Other tonal contrasts are hardly addressed. However, recent findings of Mandarin tones show that Tone 3 and Tone 4 are confusing in terms of descent slope. A big difference between previous studies and current ones is kinds of Tone 3 stimuli: previous studies used isolated Tone 3, namely, 214, and current studies used derived Tone 3, namely, 21, which is coarticulated with other tones. Spectrographic analysis was conducted. Descent slope and height of starting pitch were found critical between Tone 4 and derived Tone 3. Then three continua with ten instances for each were synthesized in respect of three different factors, descent slope, height of starting pitch, and height of ending pitch, which makes 30 stimuli total in three experiments, an AXB discrimination test, an identification test, and a lexical decision test. Results show that starting pitch height is a salient acoustic factor for 30 Mandarin natives, although descent slope was predicted more important. In addition, lexicon has an influence on ambiguous instances between endpoints of Tone 3 and Tone 4. Current findings may make contributions to understanding of perception, articulation, and lexicon during speech processing.
Native and non-native clear speech production.
Authors: Smiljanic Rajka , Bradlow Ann
Published: October 2013

Previous work established that both native and non-native clear speech increase intelligibility for native and proficient non-native listeners. However, non-native clear speech enhanced intelligibility less than native clear speech. In this study, we examine native and non-native conversational and clear speech productions with an eye on the differences in hyperarticulation strategies that may underlie a smaller clear speech intelligibility benefit. Results revealed a slower conversational speaking rate for non-native talkers compared with native talkers. Clear speaking rate was similar for both groups suggesting a limit in the speaking rate decrease in intelligibility enhancing clear speech. The durational distinction between tense and lax vowels was increased less in non-native speech due to the smaller speaking rate decrease in clear speech. Analyses of the stop voice onset time (VOT) showed that non-native talkers lengthened the voiced category in the negative VOT direction, while the voiceless category was lengthened less in clear speech. Finally, examination of vowel space expansion in clear speech revealed differences between the two talker groups reflecting non-native talkers’ inexperience in producing some of the vowel targets. Combined, these results suggest that a complex interaction of articulatory difficulty, proficiency, and native language background determines levels of non-native clear speech intelligibility.
Why do adults vary in how categorically they rate the accuracy of children’s speech?
Authors: Kaiser Eden , Munson Benjamin , Li Fangfang , Holliday Jeff , Beckman Mary , Edwards Jan , Schellinger Sarah
Published: October 2013

In a recent experiment using continuous visual analog scales (VAS) to examine adults’ perception of children’s speech accuracy, listeners varied in the extent to which they categorically perceived children’s English and non-English productions [Munson et al., American Speech-Language-Hearing Association (2008)]. Some listeners utilized all points on the VAS line for their responses, while others grouped responses around discrete locations on the line. It is hypothesized that differences in categoricity of responses across listeners might relate to listeners attending to either categorical linguistic information (i.e., identifying phonemes in a word, which would promote more categorical labeling) or gradient indexical information (i.e., identifying the child’s sex or age, which would promote more continuous labeling). If this is true, it should be possible to elicit differences in categoricity of fricative “goodness” judgments in individual listeners by priming them to listen to linguistic variables (by interleaving fricative judgment trials with trials in which they categorize the vowel spoken by the child) or indexical variables (by interleaving fricative judgment trials with trials in which they identify the child’s sex). This paper reports on an experiment designed to test this. Results will help us better understand individual response patterns in cross-language speech perception experiments.
Perceptual studies of two phonological voicing patterns.
Authors: Myers Scott
Published: October 2013

Two of the most common phonological patterns in the world's languages are final devoicing and regressive voicing assimilation. In final devoicing, there is a contrast in obstruent voicing generally, but in word-, phrase-, or syllable-final position, only voiceless obstruents are allowed (e.g., Dutch, Russian, Walloon). In regressive voicing assimilation, the first of a sequence of two obstruents is required to agree with the second in voicing (e.g., Russian, Catalan, Hebrew). These phonological patterns can be related to patterns of speech production: anticipation of the spread glottis posture in pause and laryngeal coarticulation within consonant clusters. The studies reported here investigate the perceptual consequences of these coarticulatory effects. Native speakers of English listened to words contrasting in the voicing of the final consonant (cease/seize) and identified which word they heard. The words were excised from utterance-final position or from phrase-medial position preceding a vowel, nasal, a voiced obstruent, or a voiceless obstruent. The subjects averaged about 90 percent correct identification. But they still displayed a significant bias toward identifying as voiceless the final consonant in utterance-final words as well as in words preceding a voiceless obstruent. This pattern of identification errors could be the diachronic basis of the phonological patterns.
Indexical perception in Chinese: The influence of first-language (L1) Taiwanese on second-language (L2) Mandarin.
Authors: Chang Yufen
Published: October 2013

A pilot study on indexical perception in Chinese hypothesized that L1 Taiwanese speakers’ L2 Mandarin production could be detected as having a nonnative accent. If the nonnative accent was detectable, what phonetic properties (the phonetics of consonants or vowels, or the prosody) did L1 Taiwanese speakers’ Mandarin exhibit such that these attributes entailed indexical information? Additionally, the study argued that L1 Mandarin speakers would show higher sensitivity to the nonnative accent than L1 Taiwanese speakers. The results have shown that only in sentence production, the sentences being either low-pass filtered or unfiltered, could the L1 Taiwanese talkers be possibly indexed correctly. It was also found that the listeners perceived more accurately when they encountered retroflex stimuli in monosyllabic word condition. Based on these findings, it was concluded that the prosody and the retroflex consonants seemed to reveal much of the talker’s L1 information. However, concerning the hypothesis that L1 Mandarin speakers were more sensitive to the nonnative accent, the results did not support this. The findings in this pilot study are preliminary, given the fact that the corpus was small. A bigger-scale study is being carried out to gain more insights into indexical perception in Chinese.
Linguistic experience’s influence on foreign accent detection in short, slightly accented speech.
Authors: Park Hanyong
Published: October 2013

This study examined how a listener’s linguistic experience affects the detection of foreign accent in short, slightly accented speech. Two factors were considered: Age of arrival in a second-language (L2) speaking country (AOA), and length of residence in that country (LOR). Two listener groups with the same native language (L1: Korean) but with different AOA and LOR judged the nativeness of short stimuli produced by 4 Korean-English bilinguals and 2 native speakers of American English. The stimulus length ranged from the vowel /a/ to monosyllabic and disyllabic English words. To investigate the listeners’ sensitivity patterns to different linguistic structure, the monosyllabic corpus included stimuli having both natural (i.e., CV) and unnatural syllable structures (i.e., CCV, CVC, and CCVC) as well as various segments in terms of Korean phonotactics. Results show that: (1) more experienced with L2 led to higher sensitivity to a foreign accent; (2) AOA affects foreign accent detection more than LOR; and (3) the non-native listeners were not sensitive to different linguistic structures, except in different CCV types by the more experienced listeners. The results suggest that a listener’s sensitivity to a foreign accent develops up to a certain degree, according to L2 experience.
Relation of perception training to production of codas in English as a second language.
Authors: Lopez-Soto Teresa , Kewley-Port Diane
Published: October 2013

A preliminary study has been conducted to discover whether moderate amounts of speech perception training improve accurate production even though production is not trained. The study recruited one group of eight Spanish adults who had resided less than 10 years in the USA. A set of 13 word-final English consonants was selected for training from a SPATS software module. On days 1 and 5, the group participated in both perception and production tasks with the 13 codas (pre- and post-tests). On days 2–4, the group trained with feedback for 1 h mostly with VC syllables and occasionally with sentences (speech recorded from multiple talkers). Results show: (1) with 3 h training, Spanish listeners’ perception improved significantly across the 13 codas, with greater improvement on consonant clusters than on singletons; (2) for consonants not accurately produced in the pretest, many substantially improved after only perception training; (3) several consonants with large gains in perception also showed the large improvements in production. The results from this study suggest that training only with perception can improve speech production. Experience with this protocol lays the groundwork for a series of studies to examine how perception and production are linked in learning a new language.
On prosodic variation and pronunciation aptitude: A case study of German speakers of English.
Authors: Anufryk Volha , Dogil Grzegorz
Published: October 2013

The present study investigates prosodic variation, as realized by L1 German speakers of varying pronunciation aptitude (below-average, average, and above-average) in comparison with native speakers of English. The results demonstrate the frequency of distribution of various pitch contours in read and spontaneous speech samples, English and German, on both the phonological (ToBI pitch accents and boundary tones) and phonetic levels. The latter is analyzed using a parametric intonation model (Moehler 2001). On the phonological level the rising contours, i.e., boundary tones and pitch accents, have a wider distribution in German as well as English productions of the German subjects as compared to the L1 English speakers. In German the percentages in all the aptitude groups are almost equal covering about 50% of all contours. Their English language realizations, on the other hand, are marked by a scarcer distribution of the rising pattern, with the highest percentages in the below-average and average groups and lowest by the above-average speakers. Consequently, there is a clearcut tendency for the native pattern in the German speakers’ samples. Nonetheless there is evidence for accommodation to the English variation pattern, which is strongest in the above-average aptitude group.
Gestural drift in Spanish-English speakers.
Authors: Tobin Stephen
Published: October 2013

Voice onset times (VOTs) and second vowel formants (F2s) of native speakers of Spanish were examined to extend findings on perceptually guided changes in speech production [M. L. Sancier and C. A. Fowler, J. Phon. 25, 421–426 (1995)]. Participants were recorded producing English and Spanish sentences after stays in the U.S. and in Spanish-speaking countries. Participants' English and Spanish VOTs were both significantly shorter after a stay in a Spanish-speaking country than after a stay in the U.S., supporting previous findings. While S1’s F2s were significantly lower following exposure to Spanish, as expected based on earlier results [A.R. Bradlow, J. Acoust. Soc. Am. 97(3), 1916–1924 (1995)], S2’s F2s increased. We attribute this effect to gender, pending further data acquisition. We propose that not only inter-gestural timing but also the gestural targets themselves are affected by ambient language. The systematic effect of language exposure on F2 is consistent with language-specific articulatory settings [B. Honikman (1964); Gick et al., Phonetica 61, 220–233 (2004)].
Articulating the Perceptual Assimilation Model (PAM): Perceptual assimilation in relation to articulatory organs and their constriction gestures.
Authors: Best Catherine T. , Goldstein Louis , Tyler Michael D. , Nam Hosung
Published: October 2013

A core premise of the Perceptual Assimilation Model of non-native speech perception (PAM) [Best (1995); Best & Tyler (2007)] is that adults perceive unfamiliar non-native phones in terms of articulatory similarities/dissimilarities to native phonemes and contrasts. The implied attunement to native speech emerges early: As infants begin to discern the articulatory organization of native speech, language-specific effects in non-native speech perception appear (≈6–10 months). Given that non-native phones, by definition, deviate phonetically from native ones, how can we characterize articulatory similarity in concrete, testable ways? The Articulatory Organ Hypothesis (AO) [Studdert-Kennedy & Goldstein (2003); Goldstein & Fowler (2003)] offers a possible approach, positing that infants decompose the oral-facial system into distinct articulatory organs (e.g., lips, tongue tip, tongue dorsum) and are sensitive to their actions in producing vocal tract constrictions. Thus, between-organ contrasts should be easily perceived/learned by infants and adults, whereas detection of within-organ contrasts must become attuned to the distribution of differing constriction locations/types by that organ in input speech. We discuss articulatory, attunement modeling, and perceptual evidence consistent with these predictions, and present a revised version of PAM that incorporates the AO Hypothesis and related principles of articulatory phonology [Browman & Goldstein (1991)]. [Work supported by NIH.]
Accent and intelligibility from an applied perspective.
Authors: Munro Murray J.
Published: October 2013

Listeners are remarkably sensitive to non-native patterns of speech, whether they are presented with full sentence productions, or with very short or severely degraded speech, including noisy, filtered, and temporally disrupted utterances. Furthermore, even phonetically unsophisticated listeners can reliably scale accents. From the standpoint of second language (L2) users, speaking with a detectible accent has important social consequences. One is that L2 speech is sometimes less intelligible or may require listeners to allocate more processing resources than does native speech. However, evidence also indicates that some salient phonological markers of L2 status have little or no impact on listener comprehension. Distinguishing these from accent features that reduce intelligibility is a critical concern in language pedagogy. Another consequence noted in empirical research is that accent stereotyping and negative social evaluation of accented speakers are linked to discrimination in remuneration, employment, and services. They may also be implicated in the exploitation of L2 speakers through questionable claims about the value of “accent reduction.” This synthesis of previous and new research findings highlights a number of issues concerning methodology and interpretation in L2 speech research that are relevant to language teaching and assessment, and to human rights litigation. [Research supported by SSHRC.]
Factors inducing cross-linguistic perception of illusory vowels.
Authors: Hwang Jiwon
Published: October 2013

Japanese speakers tended to hear an illusory vowel in illegal consonant sequences (Dupoux et al., 1999). Korean has no sequences of stop followed by nasal; therefore, it is expected that Korean speakers would perceive an illusory vowel in stop-nasal. In an identification task comparing Korean and English listeners on stimuli along a continuum that ranged from no vowel (igna/ikna) to a full vowel (igVna/ikVna), Korean listeners reported the presence of a vowel significantly more often than English listeners, even when there is no vowel in the stimuli. However, this effect was found only when the stop was voiced, even though [kn] and [gn] are both illegal Korean sequences. In an AXB discrimination task, Korean participants had more difficulty discriminating ‘stop-nasal’ from ‘stop-V-nasal’ than English participants, again only when the stop was voiced. The results suggest that voicing, rather than simple illegality, induces bias toward perception of illusory vowel in Korean. This is explained by the fact that in Korean, voiced stops occur only prevocalically in intersonorant position (as an allophone of voiceless obstruents). This voicing effect is reflected in Korean L2 learners’ production patterns in which they insert a vowel more often in voiced stop-nasal sequences than in voiceless stop-nasal sequences. [Work supported by NSF BCS-07460227.]