bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustic wood anomaly phenomenon in transmission and diffraction fields
Authors: Liu Jingfei , Declercq Nico F.
Published: November 2013

The notion of “Wood anomaly” in diffraction spectra in acoustics has been mostly investigated in normal reflection fields obtained from periodically corrugated interfaces between a solid and a liquid. In this work, the phenomenon is investigated both in transmission field as well as in reflection, both normal and onblique. Experiments are performed on a brass-water interface and also on a water-brass interface to obtain the reflection from these interfaces and the transmission through the interfaces. It is observed that the phenomenon appears not only in reflection but also in transmission, however it occurs at different frequencies. The study focuses on the physical origins of these phenomena and from the point of view of different possible explanations such as surface acoustic wave generation and local resonance of the corrugation.
Nonlinear frequency mixing, bubbly liquids, and standing waves: A numerical study
Authors: Vanhille Christian , Campos-Pozuelo Cleofé , Sinha Dipen N.
Published: November 2013

We study the nonlinear frequency mixing in a resonator in which a bubbly liquid (nonlinear medium) is considered. The acoustic pressure source at one end of the cavity excites the bubbly liquid at two frequencies. The cavity is set to be resonant at the difference frequency in the bubbly liquid. Numerical simulations are carried out at high and small amplitudes. Results show the formation of a difference frequency and one higher harmonic at high amplitude. [This work is part of the research project DPI2012-34613 (Spain).]
Influence of texture anisotropy on acoustoelastic birefringence in stressed wood
Authors: Liu Jinxia , Zhou Jianping , Qi Songming , Cui Zhiwen , Wang Kexie
Published: November 2013

The velocities of shear waves propagating transversely to the applied stress direction in specimen were investigated to study the effect of anisotropy on acoustoelastic birefringence for birch and elmwood specimens. The oscillation direction of the shear waves with respect to the wood plate axis was varied by rotating an ultrasonic sensor, and the relationship between the shear wave velocity and the oscillation direction was examined. The ultrasonic velocity of shear waves propagated through radial direction of wood plate specimen, transversely to the loading direction. The results indicated that when the oscillation direction of the shear wave corresponded to one of the anisotropic directions of the wood plate specimen, the shear wave velocity decreased sharply and the relationship between shear wave velocity and rotation angle tended to become discontinuous. The azimuth angles of extremum value mainly depended on the texture anisotropy and were almost not influenced by stress-induced anisotropy. Shear wave polarization preferentially followed the direction of texture anisotropy. The results of both birch and elmwood specimens showed that shear wave velocity slightly increased with compressive stress at almost all rotated angles and exhibited slight acoustoelastic birefringence effects.
A phon loudness model quantifying middle ear and cochlear sound compression
Authors: Goldstein Julius
Published: November 2013

Phon loudness data by Lydolf and Mo/ller [1997, see Suzuki and Takeshima, J. Acoust. Soc. Am. 116, 918 (2004)] at third octave frequencies 20–1000 Hz suggest evidence for Middle-Ear (ME) Sound Compression (MESC) at loudness above 60 phons. Parameters of a phon model based on sound compression by an idealized cochlear amplifier (Goldstein, 2009, 2011) were fit to the phon data at low sound levels. MESC was estimated as the excess in sound pressure levels of phon data over model predictions for 80–100 phons. MESC was found when cochlear amplifier inputs exceeded the known Acoustic Reflex Threshold (ART) of ~83 dB SPL, causing ME Muscle (MEM) contraction. Physiologically consistent first-order highpass ME transfer functions reveal a mix of MEM attenuation and attenuation at 20–100 Hz attributed to ME static pressure from pressure-field stimuli >100 dB SPL. These attenuations are isolated with the ME modeled as the low side of an RLC analog bandpass. The original data above 60 phons are modeled accurately as the sum of the two attenuations, the cochlear amplifier input, and normal ME attenuation re 1 kHz. The considerable basic information estimated from the phon data can be compared with other sources to guide further integrative research. [NIH funded 1972-04.]
Time-series evaluation of the sense of presence in audio content
Authors: Ozawa Kenji , Tsukahara Shota , Kinoshita Yuichiro , Morise Masanori
Published: November 2013

The authors have been making an effort to clarify the property of the sense of presence because this sense can be crucial for evaluating audio equipments. In our previous studies, the overall evaluation of presence was conducted for a set of audio content items, i.e., the subjects were asked to evaluate the presence of a whole content item. In this study, time-series evaluation of the sense of presence was conducted using the method of continuous judgment by category. Stimuli were 40 binaural content items with duration of approximately 30 s. They were recorded with a dummy head and presented to subjects via headphones. Twenty subjects judged the sense of presence for every moment during the presentation of each item using seven categories by pressing one of seven keys on a keyboard. After the time-series evaluation, the subjects also evaluated the overall presence of the item by seven categories. The results showed that the overall presence was highly correlated with the five-percentile exceeded presence level, which is the level exceeded for the 5% of the time under consideration. Moreover, the latency of the evaluation tended to be longer when the presence of an item was low. [Work supported by NICT.]
Less than careful speech: Exploring the roles of target duration and time varying intensity in spoken language processing
Authors: Podlubny Ryan G. , Tucker Benjamin V.
Published: November 2013

Despite substantial phonetic variation in the production of natural speech, listeners are quite adept at processing varying speech signals. Further, the recognition of spontaneous speech is a multifaceted problem where listeners are drawing information from many sources in the recognition process. Previous research has begun to outline the influence of both syntactic and semantic contributions to spoken word recognition; however, it has been argued (Ernestus et al., 2002; van de Ven et al., 2012) that such cues reach a ceiling in their contributions, and that acoustic information also aids the listener when processing language. There has been limited discussion on what information encoded within a given speech signal lends itself to more effectively processing spontaneous speech. The present study contributes to such a discussion, using responses from 85 participants in modified Cloze tasks and speech in noise manipulations, where results serve as a starting place to describe the contributions of duration and intensity in natural speech (as well as their relative effects on spoken language processing). The introduction of particular acoustic information—over and above syntactic and semantic cues—has been observed within this study as a statistically significant contributor to more effective spoken language processing.
Effects of linguistic background and noise on perception of fricatives
Authors: Stevens Megan T. , Patra Harisadhan , Vaz Petula C.
Published: November 2013

This study examined how native American English (AE) speakers perceived fricatives spoken by native AE and Bangladeshi Bengali (BB) speakers in quiet and noise. Participants included seven normal-hearing adults between 20 to 26 years of age. Participants listened to speech tokens of five fricatives, /s/, /z/, /∫/, /f/, and /v/ in the initial, medial, and final positions in the context of the point vowels /a/, /u/, /i/. Multitalker babble (MTB), speech noise, and three narrow bands of noise, 1000–2000 Hz, 2000–4000 Hz, and 500–5000 Hz at 45 dB SPL, 65 dB SPL and 85 dB SPL were used. The results suggested that listeners perceived fricatives significantly better when spoken by AE compared to BB speakers, and in quiet than in noise, especially in MTB. Listeners had the most difficulty with /z/, followed by /s/, /v/, /f, and /∫/ respectively, when tokens were spoken by BB speakers. This study may have implications for accent reduction therapy as well as for teaching English to English-language learners, especially when the phonology of the learners’ native language differs greatly from that of AE. Further studies are warranted especially due to an increasingly growing non-AE speaking population in the United States.
Effects of noise and speaker's language background on plosive perception
Authors: Brent Julie A. , Patra Harisadhan , Vaz Petula C.
Published: November 2013

This study examined the effect of speakers' language background and noise on the perception of American English (AE) plosives. Six normal-hearing, young-adults volunteered for the study. Participants listened to speech tokens of six plosives, /p/, /b/, /t/, /d/, /k/, and /g/ in the initial, medial, and final positions in the context of three vowels, /a/, /i/, and /u/, spoken by native Bangladeshi Bengali (BB) and AE speakers. Tokens were presented at 45, 65, and 65 dB SPL, either in quiet or noise. Multitalker babble, speech noise, and 1000–2000 Hz, 2000–4000 Hz, and 500–5000 Hz noise bands were used as noise. Significant differences were found with all noise types across both language backgrounds; the most difficult noise type condition being the multitalker babble. Listeners performed the best at 65 dB SPL. Listeners perceived plosives spoken by AE than BB speakers with significantly greater accuracy, more so in noise, except in the final positions. For BB-spoken tokens, listeners had the most difficulty with voicing and aspiration features. Voiceless sounds were easily confused with voiced, especially in the initial positions. This study has significant implications for accent reduction therapy as well as for teaching English to English Language Learner's. Further studies are warranted.
Phonemic word memorization strategy between second language learners and their native speakers analyzed by Rey’s Auditory Verbal Learning Test
Authors: Asano Keiko
Published: November 2013

In order to increase the numbers of vocabulary, it is effective way for L2 learners to acquire the memorization strategies. This study investigated what kinds of strategies L2 learners of English and their Native speakers of Japanese use in order to memorize and retrieve words aspects of Rey’s Auditory Verbal Learning Test (AVLT). This Auditory Verbal Leaning Test is widely spread to examine word learning and memory in the field of clinical and neuropsychological assessments. This test has two parts of stages: A list of 15 unrelated, concrete nouns is presented over three learning trials with immediate recall tested following each presentation. Next, after a delay interval of some 10 minutes with no further presentations of the list, delayed recall is assessed. The number of words correctly recalled is commonly adopted as quantitative information in clinical assessment. In addition to these procedures, after the tests participants are asked what kinds of strategies they used to memorize the words in terms of examining the process of decoding, recall and retrieval of words. Self-monitoring of memorization strategies by L2 learners of English are tended to use the phonemic or phonetic-oriented strategies whereas their Native speakers of Japanese use rather visual-oriented and episode-making. The implication on the function of different brain area activated between L2 learners and Native speakers will also be discussed.
Selective and divided attention: Spatial and pitch “spotlights” in a non-semantic task
Authors: Kishline Lindsey , Larson Eric , Maddox Ross K. , Lee Adrian KC
Published: November 2013

Listeners can reliably attend to one auditory object in the presence of many, but how good are they at dividing their attention among multiple auditory objects in a crowded auditory environment? Previously, divided attention has been looked at under the “spotlight” model of attention, borrowed from vision research, which predicts enhancement of specific spatial regions. However, the details of how these spotlights are deployed remain unknown. Here we used six competing auditory objects (distributed in azimuth in one experiment and in pitch in the other) and asked listeners to attend some and ignore others. Whether or not the target objects were contiguous tested whether they employed a single spotlight of varying size, or multiple spotlights with varying degrees of separation. Results suggest that listeners can reliably attend to multiple auditory objects. However, the level of accuracy was dependent upon the number of attended targets and their configuration.
Dynamic component analysis for multi-input/multi-output problems, with application to speech and neurophysiology
Authors: Edwards Erik , Chang Edward F.
Published: November 2013

We explore a set of methods referred to collectively as dynamic component analysis (DCA) to derive dictionaries of dynamical patterns for speech (TIMIT database). The methods use spatio-temporal singular value decomposition (ST-SVD) and common spatio-temporal pattern (CSTP) matrix computations. When used on the speech spectrogram, these yield a transformation to a new set of time series representing extracted features at reduced bandwidth. The method is computationally efficient (closed-form solutions suitable for real-time) and robust to additive noise, with diverse applications in speech processing and general multi-input/multi-output (MI/MO) modeling. When used to predict a single neural output (MI/SO), this gives an efficient new method for deriving the spectro-temporal receptive field (STRF), which is shown in our human cortical data to yield improved predictions. We also use DCA to reconstruct speech from cortical activity, wherein dynamical dictionaries for electrocortical data are derived, with application to brain-computer interfaces (BCI).
Effect of frequency variation and covariation on auditory streaming of tone sequences
Authors: Chang An-Chieh , Lutfi Robert
Published: November 2013

Recent results from our lab show the masking of one tone sequence by another to be strongly related to the information divergence of sequences, a measure of statistical separation of signals [Gilbertson et al., POMA 19, 050028 (2013)]. The present study was undertaken to determine if the same relation holds for the auditory streaming of tone sequences. An adaptive procedure was used to measure thresholds for streaming of ABAABA tone sequences wherein the frequencies of the A and B tones varied independently of one another (r = 0) or covaried within the sequence (r = 1). The procedure adapted on the difference Δ in the mean frequencies of A and B tones (normally distributed in cents) with the mean frequency of A tones fixed at 1000 Hz. For most listeners, Δ increased monotonically with increases in the variance of the tone frequencies (σ = 0-800 cents), but did not differ significantly for r = 0 and r = 1. For other listeners, Δ was a nonmonotonic function of variance and differed for r = 0 and r = 1. The results fail to support a strong relation between auditory streaming and the information divergence of tone sequences.
Maximum acceptable vibrato excursion as a function of vibrato rate in musicians and non-musicians
Authors: Vatti Marianna , Santurette Sébastien , Pontoppidan Niels H. , Dau Torsten
Published: November 2013

Human vibrato is mainly characterized by two parameters: vibrato extent and vibrato rate. These parameters have been found to exhibit an interaction both in physical recordings of singers’ voices and in listener’s preference ratings. This study was concerned with the way in which the maximum acceptable vibrato excursion varies as a function of vibrato rate in normal-hearing (NH) musicians and non-musicians. Eight NH musicians and six non-musicians adjusted the maximum vibrato excursion of a synthesized vowel for vibrato rates between 3 and 8 Hz. Individual thresholds varied across vibrato rate and, in most listeners, exhibited a peak at medium vibrato rates (5–7 Hz). Large across-subject variability was observed, and no significant effect of musical experience was found. Overall, most listeners were not solely sensitive to the vibrato excursion and there was a listener-dependent rate for which larger vibrato excursions were favored. The observed interaction between maximum excursion thresholds and vibrato rate may be due to the listeners’ judgments relying on cues provided by the rate of frequency changes (RFC) rather than excursion per se. Further studies are needed to evaluate the contribution of the RFC to vibrato perception and the possible effects of age and hearing impairment.
Predictive processing during discourse comprehension
Authors: Casillas Marisa , Frank Michael C.
Published: November 2013

We investigate children's online predictive processing as it occurs naturally, in conversation. We showed 129 children (1;0–7;0) short videos of improvised conversation between puppets, controlling for available linguistic information through phonetic manipulation: normal, prosody only (low-pass filtered), lexical only (rhythm controlled and pitch flattened), and none (multi-talker babble). We tracked their eye movements during the videos, measuring their anticipatory looks to upcoming speakers at points of turn switch (e.g., after a question and before an answer). Even one- and two-year-old children made accurate and spontaneous predictions about when a turn-switch would occur: they gazed at the upcoming speaker before they heard a response begin. By age three, children distinguished between different types of response-eliciting speech acts, looking faster to question- than non-question responses—but only when all linguistic information was available. By age seven, children’s gaze behavior also distinguished between rising and non-rising turns in the prosody only condition. These predictive skills rely on both lexical and prosodic information together, and are not tied to either type of information alone. We suggest that children integrate prosodic, lexical, and visual information to effectively predict upcoming linguistic material in conversation.
Phonological confusions in verbal working memory
Authors: Ettlinger Marc , Yund E. W. , Herron Timothy J. , Woods David L.
Published: November 2013

Previous research has shown that phonological factors impact verbal working memory (VWM) including worse memory for phonologically similar items, for phonologically longer items and for items with low-frequency phonemes and phonotactics. These effects, and others, suggest that the substrate of VWM is phonological in nature. However, if VWM is phonological, we should expect another effect: that errors made in recall should reflect phonological principles. In the present study, we examine the errors in a verbal working memory task with stimuli that include all possible CVC words and pseudo-words. This allows not only for a corroboration of previous work on consonant transpositions (i.e., spoonerisms) in memory, but also permits an examination of the newly discovered phenomenon of substitution errors in memory. The results show that the substitution errors in verbal working memory reflect the consonant confusion errors found in speech perception, with a number of interesting exceptions. Not only do these findings introduce a novel effect of the phonological nature of WM, they also bear on the question of whether VWM is articulatory or perceptual in nature, suggesting that VWM that is based on a synthesis of both the perceptual and production systems.
Information-bearing acoustic change outperforms duration in predicting sentence intelligibility in normal and simulated electric hearing
Authors: Stilp Christian
Published: November 2013

Recent research has demonstrated a strong relationship between information-bearing acoustic changes in the speech signal and speech intelligibility. The availability of information-bearing acoustic changes robustly predicts intelligibility of full-spectrum (Stilp and Kluender 2010 PNAS) and noise-vocoded sentences amidst noise interruption (Stilp et al., 2013 J.Acoust. Soc. Am.). Other research reports that duration of preserved signal also predicts intelligibility of noise-interrupted speech. These factors have only ever been investigated independently, obscuring whether one better explains speech perception. The present experiments manipulated both factors to answer this question. A broad range of sentence durations with high or low information-bearing acoustic changes were replaced by speech-shaped noise in noise-vocoded and full-spectrum sentences. Sentence intelligibility worsened with increasing noise replacement, but in both experiments, information-bearing acoustic change was a statistically superior predictor of performance. Perception relied more heavily on information-bearing acoustic changes in poorer listening conditions (in spectrally degraded sentences and amidst increasing noise replacement). Highly linear relationships between measures of information and performance suggest that exploiting information-bearing acoustic change is a shared principle underlying speech perception in acoustic and simulated electric hearing. Results demonstrate the explanatory power of information-theoretic approaches for speech perception.
Neural evidence for shared phonetic, phonological, and lexical processing of words and pseudowords
Authors: Cibelli Emily , Leonard Matthew , Chang Edward
Published: November 2013

This study uses electrocorticography (ECoG) to investigate word and pseudoword auditory processing. ECoG data are recorded from intracranial electrodes with high spatial and temporal resolution. This methodology contributes novel data to the debate over whether words and pseudowords are processed using shared streams, or whether pseudowords rely on separate sub-lexical routes. Data from left temporal lobe electrodes was recorded from two patients in a listen-and-repeat task with real words (e.g., “minority”) and pseudowords (e.g., [təmiɹɪnai]). For each electrode showing a word/pseudoword difference, regression models were fit to capture the time-varying effects of lexicality, cohort size (how many lexical items matched the current phonetic input), and cohort frequency. Preliminary results show that lexical factors had predictive power in mid- and anterior temporal electrodes. Activity peaked early in posterior electrodes and propagated forward to anterior sites. Average activity was stronger for pseudowords than words. A positive relationship was found between cohort frequency and activity; the direction of the effect varied for cohort size. Thedata is consistent with a shared streams account: along the temporal lobe, words and pseudowords share processing in acoustic, phonetic, phonological, and lexical regions, with access to stored lexical/cohort information.
Neural connectivity of voice control using structural equation modeling
Authors: Flagmeier Sabina , Ray Kimberly L. , Parkinson Amy L. , Laird Angela R. , Folks Victoria , Larson Charles , Robin Donald A.
Published: November 2013

Introduction: This study aims to model connectivity of neural regions involved in voice control. Here, we used structural equation modeling on a published dataset that employed the pitch shift paradigm. We hypothesized that our models would confirm differences in connectivity related to superior temporal gyrus during error processing of vocalization. Methods: We extracted time course data of eight regions included from 10 healthy subjects. A detailed description of subjects, MRI scanning procedures, imaging acquisition and data analysis can be found in Parkinson et al. 2012. Effective connectivity of regions activated during shift and no-shift paradigms was assessed using structural equation modeling techniques (AMOS version 19.0, SPSS, IBM). Results Consistent with our hypothesis, STG appears to play a crucial role in vocalization and error processing, showing increased participation of the right hemisphere during the shift condition than the no shift condition. Furthermore, left inferior frontal gyrus displays significant contribution to the modulation of vocal control through connections with PMC that change in response to the shift condition. Conclusions: Results indicated changes in connectivity of the voice network related to error detection and correction. Our models indicate hemispheric sensitivity to different elements of the auditory feedback and highlight the importance of examining network connectivity.
Human superior temporal gyrus encoding of speech sequence probabilities
Authors: Leonard Matthew K. , Bouchard Kristofer , Chang Edward F.
Published: November 2013

Spoken word representations are hypothesized to be built from smaller segments of the speech signal, including phonemes and acoustic features. The language-level statistics of sound sequences (“phonotactics”) are speculated to play a role in integrating sub-lexical representations into words in the human brain. In four neurosurgical patients, we recorded electrocorticographic (ECoG) neural activity directly from the brain surface while they listened to spoken real and pseudo words with varying transition probabilities (TPs) between the consonants and vowels (Cs and Vs) in a set of CVC stimuli. Electrodes over left superior temporal gyrus (STG) were sensitive to TPs in a way that suggested dynamic, near real-time tracking of the speech input. TP effects were seen independently from activity explained by acoustic variability as measured by each electrode’s spectrotemporal receptive field (STRF). Furthermore, population-level analyses of STG electrodes demonstrated that TP effects were different for real vs pseudo words. These results support the hypothesis that lifelong exposure to phonetic sequences shapes the organization and synaptic weights of neural networks that process sounds in a given language, and that phonotactic information is used dynamically to integrate sub-lexical speech segments toward lexical representations.
Cortical processing of audiovisual speech perception in infancy and adulthood
Authors: Zhang Yang , Cheng Bing , Koerner Tess , Cao Christine , Carney Edward , Wang Yue
Published: November 2013

The ability to detect auditory-visual correspondence in speech is an early hallmark of typical language development. Infants are able to detect audiovisual mismatches for spoken vowels such as /a/ and /i/ as early as 4 months of age. While adult event-related potential (ERP) data have shown an N300 associated with the detection of audiovisual incongruency in speech, it remains unclear whether similar responses can be elicited in infants. The present study collected ERP data in congruent and incongruent audiovisual presentation conditions for /a/ and /i/ from 21 typically developing infants (6~11 month of age) and 12 normal adults (18~45 years). The adult data replicated the N300 in the parietal electrode sites for detecting audiovisual incongruency in speech, and minimum norm estimation (MNE) showed the primary neural generator in the left superior temporal cortex for the N300. Unlike the adults, the infants showed a later N400 response in the centro-frontal electrode sites, and scalp topography as well as MNE results indicated bilateral activation in the temporal cortex with right-hemisphere dominance. Together, these data indicate important developmental changes in the timing and hemispheric laterality patterns for detecting audiovisual correspondence in speech.
Lexical tone and consonant perception in subtypes of Schizophrenia
Authors: Tsao Feng-Ming , Chiang Shih-Kuang , Liu Huei-Mei
Published: November 2013

Auditory hallucination is one of diagnostic criteria of schizophrenia and might negatively affect speech perception. Among subtypes of schizophrenia, the persistent delusion/hallucination (PDH) group persistently shows auditory hallucinations after 6 months of admission. This study aims to examine whether hallucinations affect lexical tone and consonant perception in Mandarin-speaking adults. Two groups of adults with chronic schizophrenia, PDH (n =15, mean age = 44 yr) and non-hallucination group (n =17, mean age = 39 yr), and age-matched control group (n = 16, mean age = 36 yr) in Taiwan were tested. For lexical tone perception, results showed that adults with schizophrenia were less accurate than typical controls on discriminating the lexical tones, and the PDH group performed poor than patients without hallucination. The lexical tone accuracy negatively correlates with the severity of schizophrenic symptoms (r = −0.559, p < 0.001, measured with Positive and Negative Syndrome Scale for schizophrenia). For consonant perception, patient groups showed poor perceptual organizations for affricates than control group. Moreover, the perceptual organization of PDH group is more distorted than non-hallucination group. In brief, adults with chronic schizophrenia exhibit speech perception deficits, and these deficits might be the result of a distorted perceptual organization.
The effect of working memory capacity on sequencing errors in child speech
Authors: Choe Wook Kyung , Redford Melissa A.
Published: November 2013

The current study investigated the effect of working memory on the distribution and other characteristics of sequencing errors in school-aged children’s production of sentence-length tongue twisters. Our goal was to understand the relationship between memory and speech planning in child speech. Working memory was assessed using subtests from the CTOPP (Wagner et al., 1999). Errors were elicited by asking 33 children (6-to-9-year-olds) to read different tongue twisters multiple times. Anticipatory and perseveratory errors were identified and categorized; strong and weak prosodic boundaries were also identified. Results showed that the children with larger working memory capacity produced significantly shorter prosodic phrases than those with smaller working memory capacity. Otherwise, the distribution and other characteristics of errors in the former group were more adult-like than those of the latter group: more errors toward the end of prosodic phrases (Choe and Redford, 2012); lower error rates (Wijnen, 1992); and more anticipatory than perseveratory errors (Vousden and Maylor, 2006). We suggest that these results are consistent with more structured speech plans in children with larger working memory capacity than in those with smaller capacity. [This research was supported by NICHD.]
Learning words from multiple talkers helps children's production but not perception
Authors: Davis Andrea K. , Gerken LouAnn
Published: November 2013

Phonetic variation between speakers promotes generalization when a listener is learning new speech sounds or new word forms (Lively et al., 1993; Richtsmeier et al., 2009; Rost and McMurray, 2009, 2010). In the latter two studies, infant learners were better able to discriminate newly learned words produced by new talkers when trained with multiple talkers. But is variation always helpful for generalization? A variety of factors may influence whether variation is beneficial, including the amount of prior experience with the language, or whether the test is on perception vs production. A study with pre-schoolers addresses these potential influences on whether variation is helpful for learning word forms. Children aged 2.5–5 learned four new words, from either multiple talkers or a single talker. They were then asked to detect a puppet's mispronunciations, and then to produce the new words. Results suggest that for older as well as younger pre-schoolers, learning with variation does not help with detecting mispronunciations of the word. However, results of Richtsmeier et al. are replicated, with children producing words more accurately when they learned the words from multiple talkers. This suggests that speakers use different representations for perception and production, at least when a word is newly learned.
Production and perception of tones by English speaking children
Authors: Shport Irina A. , Redford Melissa A. , Chandrasekaran Bharath
Published: November 2013

Production and perception may not be correlated in adult learners of tonal languages (Bent, 2005). We examined whether these abilities might however be correlated in children. Thirty-one children (age 7;1–9;0) and 20 adults participated in tone learning experiment. They repeated 8 “Martian” words, varying in tone patterns (high, rising, falling-rising, falling) and in tone location (first syllable, second syllable), 4 times in random order over each training block (3). Production accuracy was assessed using discriminant analysis. Mean F0, excursion size, final velocity, and duration were the predictor variables. Tone discrimination was measured in an AX task based on low-pass versions of the same “words” used in training. Children’s working memory capacity, a known predictor of first language acquisition (Gathercole and Baddeley, 1993), was also measured. The results revealed no correlation between production and perception in adults. In contrast, production accuracy in the first training block, perceptual discrimination (d′), and working memory combined to predict production accuracy in the final training block (R 2 = 0.43) in children. The results suggest that sensitivity to pitch variation and working memory may influence second language tone learning in children. [Work support by NICHD.]
Contextual influences on speech perception in developmental populations
Authors: Theodore Rachel M. , Campbell Jean , Bisaillon MaryKate , Roscillo Devin
Published: November 2013

A major goal of speech perception research has been to describe how listeners recognize individual consonants and vowels from the speech stream given rampant acoustic-phonetic variability in their instantiation. Findings in healthy adults indicate that listeners achieve perceptual stability, at least in part, by dynamically adjusting phonetic boundaries to accommodate contextual influences in speech production. The current work examines the developmental trajectory of such functional plasticity in typically developing children. Across two experiments, we examined the influence of speaking rate and place of articulation on stop consonant identification. Stimuli consisted of three voice-onset-time continua: “goal” to “coal” at a fast speaking rate, “goal” to “coal” at a slow speaking rate, and “bowl” to “pole” at a slow speaking rate. The results showed that 8-10-year-old children are sensitive to how these contextual influences pattern in speech production. Specifically, the identification responses indicated that the voicing boundary was located at longer VOTs for the slow compared to the fast speaking rate continuum and for the velar compared to the labial continuum. These findings suggest that perceptual sensitivity to contextual influences in speech production emerges early in development, illustrating a critical role for functional plasticity toward the healthy end-state system.
Data-driven intonational phonology
Authors: Anumanchipalli Gopala Krishna , Black Alan W , Oliveira Luis C.
Published: November 2013

Intonational Phonology deals with the systematic way in which speakers effectively use pitch to add appropriate emphasis to the underlying string of words in an utterance. Two widely discussed aspects of pitch are the pitch accents and boundary events. These provide an insight into the sentence type, speaker attitude, linguistic background, and other aspects of prosodic form. The main hurdle, however, is the difficulty in getting annotations of these attributes in “real” speech. Besides being language independent, these attributes are known to be subjective and prone to high inter-annotator disagreements. Our investigations aim to automatically derive phonological aspects of intonation from large speech databases. Recurring and salient patterns in the pitch contours, observed jointly with an underlying linguistic context are automatically detected. Our computational framework unifies complementary paradigms such as the physiological Fujisaki model, Autosegmental Metrical phonology, and elegant pitch stylization, to automatically (i) discover phonologically atomic units to describe the pitch contours and (ii) build inventories of tones and long term trends appropriate for the given speech database, either large multi-speaker or single speaker databases, such as audiobooks. We successfully demonstrate the framework in expressive speech synthesis. There is also immense potential for the approach in speaker, style, and language characterization.
Improving speech enhancement algorithms by incorporating visual information
Authors: Tekin Ender , Coughlan James , Simon Helen
Published: November 2013

In speech perception, the visual information obtained by observing the speaker’s face can account for up to 6 and 10 dB improvements in the presence of wide-band Gaussian and speech-babble noise, respectively. Current hearing aids and other speech enhancement devices do not utilize the visual input from the speaker's face, limiting their functionality. To alleviate this shortcoming, audio-visual speech enhancement algorithms have been developed by including video information in the audio processing. We developed an audio-visual voice activity detector (VAD) that combines audio features such as long-term spectral divergence with video features such as spatio-temporal gradients of the mouth area. The contributions of various features are learned by maximizing the mutual information between the audio and video features in an unsupervised fashion. Segmental SNR (SSNR) values were estimated to compare the benefits of audio-visual and conventional audio-only VADs. VAD outputs were utilized by an adaptive Wiener filter to estimate the noise spectrum, and enhance speech corrupted by Gaussian and speech-babble noise. The SSNR improvements were similar in low-noise conditions, but the output using the audio-visual VAD was on average 8 dB better in high-noise. This shows that video can provide complementary information when audio is very noisy, leading to significant performance improvements.
Direct to reverberation ratio based two channel dereverberation for automatic speech recognition
Authors: Baek Soonho , Kang Hong-Goo
Published: November 2013

This paper proposes a spectral subtraction based two channel dereverberation algorithm for automatic speech recognition (ASR). By observing the fact that the accuracy of ASR system with reverberant speech highly relates to the amount of reverberant component, this paper focuses on designing a novel reverberant component estimator. Especially, the proposed algorithm utilizes the relationship between direct to reverberation ratio (DRR) and the power of reverberant components, then the estimated value is further adjusted to maximize the word accuracy of recognizer. Experimental results verify that the proposed estimator improves ASR performance in various reverberant environments.
The (null) effect of spectral estimator on the estimation of spectral moments
Authors: Reidy Patrick
Published: November 2013

The spectra of English voiceless sibilants [s] and [š], when computed with traditional estimators, such as the DFT calculated over an interval multiplied with a data window, exhibit relatively large variance, which is believed to introduce error in the estimation of linguistically meaningful features, such as the first four spectral moments (centroid, variance, skewness, and kurtosis). In an effort to reduce this error, it is becoming common practice to compute such features from a multitaper spectrum (MTS)—an estimator, which asymptotically has a fraction of the DFT's variance. However, while the difference in variance has been demonstrated mathematically when the number of data samples approaches infinity, it remains an open question whether the MTS engenders more precise spectral features when estimated from the short intervals that are relevant for comparing [s] and [š]. To evaluate this issue empirically, the first four moments were estimated, with an MTS and a hamming-windowed DFT, from the middle 40-ms of 2061 word-initial tokens of [s] and [š] in utterances of English words recorded by 80 children and 20 adult native speakers. Paired t-tests revealed no significant difference between the two estimators for any of the spectral moments.
Technique for mapping fast speech
Authors: Lawrence Jesse , da Silva Lucia
Published: November 2013

This study investigates a novel technique for mapping normal speech to fast speech based on extracted F0 and amplitude contours. Standard methods of increasing the rate of recorded speech use mechanical or digital linear time compression, producing a speech signal that is shorter in duration. However, these methods shift all acoustic parameters in linear fashion without taking into consideration the interaction between speaking rate and stress patterns. This is sharply contrasted with the nonlinear effects observed when a speaker naturally increases speech rate. Our approach, which makes use of TANDEM-STRAIGHT (Kawahara et al. 2008), a speech analysis and resynthesis system, compares the F0 and amplitude contours of normal speech to the F0 and amplitude contours of naturally produced fast speech in order to derive coefficients, which are used to map novel instances of normal speech to fast speech. The resulting fast speech shows more of the nonlinear characteristics of naturally produced fast speech by attending to the interaction between speaking rate and stress patterns, and eliminates the need for post-process pitch correction inherent to time compression methods. This technique therefore represents an advance in the state of the art, with applications in research and commercial technology.
The Meet a Friend corpus of spontaneous speech: New data, initial results
Authors: Henetz Tania , Casillas Marisa
Published: November 2013

We introduce a new collection of 60 spontaneous speech recordings that we are making available to the wider linguistic community. We video and audio recorded sixty pairs of American English speakers as they talked freely for 20 min about four general topics (e.g., pets, food, movies). Half of the pairs came in as friends, half as strangers. The corpus contains one third each of female-female, female-male, and male-male speaker pairs. Before the recording, each participant completed a Ten Item Personality (TIPI) assessment. Afterwards, each participant gave a review of their and their partner’s behavior during the conversation. Each recording is then transcribed in three passes by separate transcribers and applied to the audio recording using the Penn Phonetics Lab Forced Aligner for extended search and automated extraction abilities. We present a few initial results using these new data. For example, by extracting turn-switch gaps and comparing them to participant ratings, we find support from these naturalistic data for prior, controlled experimental work showing that inter-turn gap times relate to social evaluations of the ongoing interaction. We compare disfluency between friend- and stranger-pairs, linking these patterns to any disfluency accommodation that occurred during the interaction.
High-frequency sediment acoustics over transitions from dense shell hash to mud: Repeat surveys at 7 frequencies from 150 kHz to 450 kHz
Authors: de Moustier Christian , Kraft Barbara J.
Published: November 2013

Seafloor acoustic backscatter data were collected with a high-frequency multibeam echo-sounder offshore Panama City Beach, FL, in May 2013, as part of the Target and Reverberation Experiment 2013 (TREX13) sponsored by the Office of Naval Research (ONR). In this context, 7 repeat surveys of a 3 km2 area were done at individual frequencies ranging from 150 to 450 kHz, in 50 kHz increments. The regional seafloor terrain is characterized by a ridge-swale topography. Sediments in the area surveyed include mixtures of sand and mud in various proportions, augmented with shell hash whose distribution appears to be driven by bottom currents. This is inferred from maps of acoustic backscatter intensity data that show sharp boundaries (>10 dB) between dense shell hash accumulations and mud. These sediment acoustic transitions occur over a few meters and extend across the survey area, usually at the bottom of a swale. The transition pattern is consistent at all frequencies in the 7 maps of acoustic backscatter intensity (one per frequency). [Work funded by ONR Code 32OA, with sonar technical support by Teledyne-RESON.]
Correlations between transmission loss measurements and sediment type
Authors: George Jacob , Harvey David W.
Published: November 2013

We report the results of a study correlating mid-frequency transmission loss (TL) measurements with properties of nearby sediment core samples. A large number of measurements were made in shallow water areas with water depths ranging from 50 to 160 m. The statistical distributions of the derived bottom-loss values are found to be nearly invariant to various sediment properties derived from the corresponding core samples. These properties include seafloor sound speed, density, and porosity as well as a number of others. It is shown from Parabolic Equation model calculations that use Hamilton’s values for the different sediment types [J. Acoust. Soc. Am. 68, 1313 (1980)] that the TL can vary by 15 dB or more at a range of 20 km. Therefore the absence of substantial bias in the data with respect to sediment types is somewhat surprising and worth investigation. The possible explanations, such as high spatial variability of seafloor processes including presence of ripples, gas, and other causes are being investigated and will be discussed. [Approved for public release].
High-frequency sediment sound speed and attenuation measurements during TREX13 (Target and Reverberation Experiment 2013) with a new portable velocimeter
Authors: Guillon Laurent , Demoulin Xavier , Hefner Brian T. , Zou Dapeng
Published: November 2013

During the Target and Reverberation Experiment 2013 (TREX13), high-frequency measurements of sediment sound speed and attenuation were collected throughout the experiment site. These measurements were performed using the INSEA, a diver-portable array of sources and receivers conceived and developed by French companies in collaboration with research institutions. During each deployment of the instrument, the INSEA was inserted 10–15 cm into the sediment and narrow-band pulses covering the 70 to 350 kHz range were transmitted through the sediment. The sound speed is determined from the time-of-flight and attenuation is determined from the amplitude ratio of the transmissions through the sediment and through the water. The variability of the TREX13 site made it possible to collect data in several different sediment types including mud, silty-sand, and sand sediments each with low to high concentrations of shells. In addition to the acoustic measurements, diver cores and shell samples were also collected. The sound speed and attenuation measured in these sediments are presented and discussed. [Work supported by DGA, ONRG, and SERDP.]