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The goal of this study was to assess recognition of foreign-accented speech of varying intelligibility and linguistic complexity in older adults. It is important to understand the factors that influence the recognition of this commonly encountered type of speech, in a population that remains understudied in this regard.A repeated measures design was used. Listeners repeated back linguistically simple and complex sentences heard in noise. The sentences were produced by three talkers of varying intelligibility: one native American English, one foreign-accented talker of high intelligibility and one foreign-accented talker of low intelligibility. Percentage word recognition in sentences was measured.Twenty-five older listeners with a range of hearing thresholds participated.We found a robust interaction between talker intelligibility and linguistic complexity. Recognition accuracy was higher for simple versus complex sentences, but only for the native and high intelligibility foreign-accented talkers. This pattern was present after effects of working memory capacity and hearing acuity were taken into consideration.Older listeners exhibit qualitatively different speech processing strategies for low versus high intelligibility foreign-accented talkers. Differences in recognition accuracy for words presented in simple versus in complex sentence contexts only emerged for speech over a threshold of intelligibility.

Foreign-accented speech recognition is typically tested with linguistically simple materials, which offer a limited window into realistic speech processing. The present study examined the relationship between linguistic structure and talker intelligibility in several sentence-in-noise recognition experiments. Listeners transcribed simple/short and more complex/longer sentences embedded in noise. The sentences were spoken by three talkers of varying intelligibility: one native, one high-, and one low-intelligibility non-native English speakers. The effect of linguistic structure on sentence recognition accuracy was modulated by talker intelligibility. Accuracy was disadvantaged by increasing complexity only for the native and high intelligibility foreign-accented talkers, whereas no such effect was found for the low intelligibility foreign-accented talker. This pattern emerged across conditions: low and high signal-to-noise ratios, mixed and blocked stimulus presentation, and in the absence of a major cue to prosodic structure, the natural pitch contour of the sentences. Moreover, the pattern generalized to a different set of three talkers that matched the intelligibility of the original talkers. Taken together, the results in this study suggest that listeners employ qualitatively different speech processing strategies for low- versus high-intelligibility foreign-accented talkers, with sentence-related linguistic factors only emerging for speech over a threshold of intelligibility. Findings are discussed in the context of alternative accounts.

OBJECTIVES The role of subcortical synchrony in speech-in-noise (SIN) recognition and the frequency-following response (FFR) was examined in multiple listeners with auditory neuropathy. Although an absent FFR has been documented in one listener with idiopathic neuropathy who has severe difficulty recognizing SIN, several etiologies cause the neuropathy phenotype. Consequently, it is necessary to replicate absent FFRs and concomitant SIN difficulties in patients with multiple sources and clinical presentations of neuropathy to elucidate fully the importance of subcortical neural synchrony for the FFR and SIN recognition. DESIGN Case series. Three children with auditory neuropathy (two males with neuropathy attributed to hyperbilirubinemia, one female with a rare missense mutation in the OPA1 gene) were compared to age-matched controls with normal hearing (52 for electrophysiology and 48 for speech recognition testing). Tests included standard audiological evaluations, FFRs, and sentence recognition in noise. The three children with neuropathy had a range of clinical presentations, including moderate sensorineural hearing loss, use of a cochlear implant, and a rapid progressive hearing loss. RESULTS Children with neuropathy generally had good speech recognition in quiet but substantial difficulties in noise. These SIN difficulties were somewhat mitigated by a clear speaking style and presenting words in a high semantic context. In the children with neuropathy, FFRs were absent from all tested stimuli. In contrast, age-matched controls had reliable FFRs. CONCLUSION Subcortical synchrony is subject to multiple forms of disruption but results in a consistent phenotype of an absent FFR and substantial difficulties recognizing SIN. These results support the hypothesis that subcortical synchrony is necessary for the FFR. Thus, in healthy listeners, the FFR may reflect subcortical neural processes important for SIN recognition.

Memory for speech benefits from linguistic structure. Recall is better for sentences than for random strings of words (the “sentence superiority effect”; SSE), and evidence suggests that ongoing speech may be organized advantageously as clauses in memory (recall by word position shows within-clause U shape). In this study, we examined the SSE and clause-based organization for closed-set speech materials with low semantic predictability and without typical prosody. An overall SSE was observed and accuracy by word position was enhanced at the clause boundaries for these materials. Next, we tested the effects of mental manipulation on the SSE and clause-based organization. Listeners heard word strings that were syntactic, were arranged syntactically then presented backwards, or were random draws. Participants responded to materials as presented or in reversed order, requiring mental manipulation. Clause-level organization was apparent only for materials presented in syntactic order regardless of response order. After accounting for benefits due to reductions in uncertainty for these close-set materials, an SSE was present for syntactic materials regardless of response order, and for the syntactic backwards condition with reverse-order response (yielding a syntactically correct sentence in the response). Thus, the SSE was both resistant to and could be obtained following mental manipulation.

Second-language (L2) speech is consistently slower than first-language (L1) speech, and L1 speaking rate varies within- and across-talkers depending on many individual, situational, linguistic, and sociolinguistic factors. It is asked whether speaking rate is also determined by a language-independent talker-specific trait such that, across a group of bilinguals, L1 speaking rate significantly predicts L2 speaking rate. Two measurements of speaking rate were automatically extracted from recordings of read and spontaneous speech by English monolinguals (n = 27) and bilinguals from ten L1 backgrounds (n = 86): speech rate (syllables/second), and articulation rate (syllables/second excluding silent pauses). Replicating prior work, L2 speaking rates were significantly slower than L1 speaking rates both across-groups (monolinguals' L1 English vs bilinguals' L2 English), and across L1 and L2 within bilinguals. Critically, within the bilingual group, L1 speaking rate significantly predicted L2 speaking rate, suggesting that a significant portion of inter-talker variation in L2 speech is derived from inter-talker variation in L1 speech, and that individual variability in L2 spoken language production may be best understood within the context of individual variability in L1 spoken language production.

Recordings of Spanish and English sentences by switched-dominance bilingual (SDB) Spanish (i.e., L2-dominant Spanish-English bilinguals) and by L1-dominant Spanish and English controls were presented to L1-dominant Spanish and English listeners, respectively. At –4 dB signal-to-noise ratio (SNR), Spanish and English productions by SDBs were equally intelligible with both reaching L1-dominant control levels. At –8 dB SNR, SDB English intelligibility matched that of L1-dominant English controls, yet SDB Spanish intelligibility was significantly lower than that of L1-dominant Spanish controls. These results emphasize that extended (but not early) exposure is both necessary and sufficient for robust speech learning.

Adaptation to foreign-accented sentences can be guided by knowledge of the lexical content of those sentences, which, being an exact match for the target, provides feedback on all linguistic levels. The extent to which this feedback needs to match the accented sentence was examined by manipulating the degree of match on different linguistic dimensions, including sub-lexical, lexical, and syntactic levels. Conditions where target-feedback sentence pairs matched and mismatched generated greater transcription improvement over non-English speech feedback, indicating listeners can draw upon sources of linguistic information beyond matching lexical items, such as sub- and supra-lexical information, during adaptation.

Bilinguals are known to perform worse than monolinguals on speech-in-noise tests. However, the mechanisms underlying this difference are unclear. By varying the amount of linguistic information available in the target stimulus across five auditory-perception-in-noise tasks, we tested if differences in language-independent (sensory/cognitive) or language-dependent (extracting linguistic meaning) processing could account for this disadvantage. We hypothesized that language-dependent processing differences underlie the bilingual disadvantage and predicted that it would manifest on perception-in-noise tasks that use linguistic stimuli. We found that performance differences between bilinguals and monolinguals varied with the linguistic processing demands of each task: early, high-proficiency, Spanish–English bilingual adolescents performed worse than English monolingual adolescents when perceiving sentences, similarly when perceiving words, and better when perceiving tones in noise. This pattern suggests that bottlenecks in language-dependent processing underlie the bilingual disadvantage while language-independent perception-in-noise processes are enhanced.

The present study provides evidence of a positive correlation between L1 and L2 intelligibility for bilingual talkers. Each talker in a group of Mandarin-English and Korean-English bilinguals was recorded producing simple sentences in each of their languages. The recordings were then presented to native listeners of the language-being-spoken in a test of sentence-in-noise recognition to yield a pair of L1 and L2 intelligibility scores for each talker based on the proportion of words correctly recognized. For all talkers, their L2 speech (i.e., Mandarin- or Korean-accented English) was consistently lower in intelligibility than their L1 speech (i.e., native accented Mandarin or Korean). This dissociation between L1-L2 speech intelligibility was evident in different intelligibility scores at comparable signal-to-noise ratios (as much as 35 percentage points for the Mandarin-English bilinguals) and in the required boost in signal-to-noise ratio to achieve comparable intelligibility (>8–10 dB). Critically, L1 and L2 intelligibility scores within the bilingual talkers were strongly positively correlated: Talkers with relatively high intelligibility in L1 also achieved relatively high intelligibility in L2. These results indicate a persistent influence of talker-specific trait characteristics that combine with, rather than are overwhelmed by, language-specific and dominance-dependent influences in bilingual speech production.

Language acquisition typically involves periods when the learner speaks and listens to the new language, and others when the learner is exposed to the language without consciously speaking or listening to it. Adaptation to variants of a native language occurs under similar conditions. Here, speech learning by adults was assessed following a training regimen that mimicked this common situation of language immersion without continuous active language processing. Experiment 1 focused on the acquisition of a novel phonetic category along the voice-onset-time continuum, while Experiment 2 focused on adaptation to foreign-accented speech. The critical training regimens of each experiment involved alternation between periods of practice with the task of phonetic classification (Experiment 1) or sentence recognition (Experiment 2) and periods of stimulus exposure without practice. These practice and exposure periods yielded little to no improvement separately, but alternation between them generated as much or more improvement as did practicing during every period. Practice appears to serve as a catalyst that enables stimulus exposures encountered both during and outside of the practice periods to contribute to quite distinct cases of speech learning. It follows that practice-plus-exposure combinations may tap a general learning mechanism that facilitates language acquisition and speech processing.

While indexical information is implicated in many levels of language processing, little is known about the internal structure of the system of indexical dimensions, particularly in bilinguals. A series of three experiments using the speeded classification paradigm investigated the relationship between various indexical and non-linguistic dimensions of speech in processing. Namely, we compared the relationship between a lesser-studied indexical dimension relevant to bilinguals, which language is being spoken (in these experiments, either Mandarin Chinese or English), with: talker identity (Experiment 1), talker gender (Experiment 2), and amplitude of speech (Experiment 3). Results demonstrate that language-being-spoken is integrated in processing with each of the other dimensions tested, and that these processing dependencies seem to be independent of listeners’ bilingual status or experience with the languages tested. Moreover, the data reveal processing interference asymmetries, suggesting a processing hierarchy for indexical, non-linguistic speech features.

Prior research has demonstrated that listeners are sensitive to changes in the indexical (talker-specific) characteristics of speech input, suggesting that these signal-intrinsic features are integrally encoded in memory for spoken words. Given that listeners frequently must contend with concurrent environmental noise, to what extent do they also encode signal-extrinsic details? Native English listeners’ explicit memory for spoken English monosyllabic and disyllabic words was assessed as a function of consistency versus variation in the talker’s voice (talker condition) and background noise (noise condition) using a delayed recognition memory paradigm. The speech and noise signals were spectrally-separated, such that changes in a simultaneously presented non-speech signal (background noise) from exposure to test would not be accompanied by concomitant changes in the target speech signal. The results revealed that listeners can encode both signal-intrinsic talker and signal-extrinsic noise information into integrated cognitive representations, critically even when the two auditory streams are spectrally non-overlapping. However, the extent to which extra-linguistic episodic information is encoded alongside linguistic information appears to be modulated by syllabic characteristics, with specificity effects found only for monosyllabic items. These findings suggest that encoding and retrieval of episodic information during spoken word processing may be modulated by lexical characteristics.

This study examined the influence of background language variation on speech recognition. English listeners performed an English sentence recognition task in either “pure” background conditions in which all trials had either English or Dutch background babble or in mixed background conditions in which the background language varied across trials (i.e., a mix of English and Dutch or one of these background languages mixed with quiet trials). This design allowed the authors to compare performance on identical trials across pure and mixed conditions. The data reveal that speech-in-speech recognition is sensitive to contextual variation in terms of the target-background language (mis)match depending on the relative ease/difficulty of the test trials in relation to the surrounding trials.

Background: Masking release for an English sentence-recognition task in the presence of foreign-accented English speech compared with native-accented English speech was reported in Calandruccio et al (2010a). The masking release appeared to increase as the masker intelligibility decreased. However, it could not be ruled out that spectral differences between the speech maskers were influencing the significant differences observed. Purpose: The purpose of the current experiment was to minimize spectral differences between speech maskers to determine how various amounts of linguistic information within competing speech affect masking release. Research Design: A mixed-model design with within-subject (four two-talker speech maskers) and between-subject (listener group) factors was conducted. Speech maskers included native-accented English speech and high-intelligibility, moderate-intelligibility, and low-intelligibility Mandarin-accented English. Normalizing the long-term average speech spectra of the maskers to each other minimized spectral differences between the masker conditions. Study Sample: Three listener groups were tested, including monolingual English speakers with normal hearing, nonnative English speakers with normal hearing, and monolingual English speakers with hearing loss. The nonnative English speakers were from various native language backgrounds, not including Mandarin (or any other Chinese dialect). Listeners with hearing loss had symmetric mild sloping to moderate sensorineural hearing loss. Data Collection and Analysis: Listeners were asked to repeat back sentences that were presented in the presence of four different two-talker speech maskers. Responses were scored based on the key words within the sentences (100 key words per masker condition). A mixed-model regression analysis was used to analyze the difference in performance scores between the masker conditions and listener groups. Results: Monolingual English speakers with normal hearing benefited when the competing speech signal was foreign accented compared with native accented, allowing for improved speech recognition. Various levels of intelligibility across the foreign-accented speech maskers did not influence results. Neither the nonnative English-speaking listeners with normal hearing nor the monolingual English speakers with hearing loss benefited from masking release when the masker was changed from native-accented to foreign-accented English. Conclusions: Slight modifications between the target and the masker speech allowed monolingual English speakers with normal hearing to improve their recognition of native-accented English, even when the competing speech was highly intelligible. Further research is needed to determine which modifications within the competing speech signal caused the Mandarin-accented English to be less effective with respect to masking. Determining the influences within the competing speech that make it less effective as a masker or determining why monolingual normal-hearing listeners can take advantage of these differences could help improve speech recognition for those with hearing loss in the future.

I will describe the “progressive co-authorship cycle” as a strategy for promoting student publishing success. Crucial points in this progression are: (1) an initial phase in which the advisor is the lead author on a co-authored publication, (2) a middle phase in which the student and advisor are both in transition, and (3) a final phase in which the role reversal is complete and the student is the lead author on a co-authored publication. Each phase serves a unique purpose in the overall progression: modelling of good practice (phase 1), infusion of new energy and dynamism (phase 2), and finally, consolidation of a new and more equitable partnership (phase 3). I will emphasize that, as the fulcrum of the cycle, the middle phase is the most important yet easiest-to-neglect phase in a student-advisor relationship. During this phase, the student develops other co-authorship opportunities (e.g. with fellow students and/or other mentors). By infusing new ideas and research strategies into the mentor-mentee relationship, these “external” collaborations can be particularly enriching for phase 3. While this progression is rarely realized in clearly demarcated phases, it can provide a guiding framework for mentoring, and specifically for supporting student publishing success.I will describe the “progressive co-authorship cycle” as a strategy for promoting student publishing success. Crucial points in this progression are: (1) an initial phase in which the advisor is the lead author on a co-authored publication, (2) a middle phase in which the student and advisor are both in transition, and (3) a final phase in which the role reversal is complete and the student is the lead author on a co-authored publication. Each phase serves a unique purpose in the overall progression: modelling of good practice (phase 1), infusion of new energy and dynamism (phase 2), and finally, consolidation of a new and more equitable partnership (phase 3). I will emphasize that, as the fulcrum of the cycle, the middle phase is the most important yet easiest-to-neglect phase in a student-advisor relationship. During this phase, the student develops other co-authorship opportunities (e.g. with fellow students and/or other mentors). By infusing new ideas and research strategies into the mentor-mentee re...

Foreign-accented speech can be difficult to understand but listeners can adapt to novel talkers and accents with appropriate experience. Previous studies have demonstrated talker-independent but accent-dependent learning after training on multiple talkers from a single language background. Here, listeners instead were exposed to talkers from five language backgrounds during training. After training, listeners generalized their learning to novel talkers from language backgrounds both included and not included in the training set. These findings suggest that generalization of foreign-accent adaptation is the result of exposure to systematic variability in accented speech that is similar across talkers from multiple language backgrounds.

In this study, we consider how native status and signal degradation influence French listeners’ segmentation of an incoming speech stream containing liaison , a phonological process that misaligns word and syllable boundaries. In particular, we investigate how both first language (L1) and second language (L2) French listeners compensate for the syllable-word misalignment associated with liaison while segmenting French speech, and whether compensation-for-liaison strategies differ with decreasing signal-to-noise ratios. We consider the degree to which listeners rely on lexical knowledge, acoustic-phonetic cues, and distributional information to accomplish this compensation. Listeners completed a word identification task in which they heard adjective-noun sequences with or without liaison and were presented with the word or nonword alternatives for each noun that would result depending on whether the listener did or did not compensate for liaison. Results showed that both L1-French and L2-French listeners generally preferred lexically acceptable parses over those that resulted in a stranded nonword, and both groups gave significantly fewer lexically acceptable parses under harder listening conditions. However, the L2-French listeners demonstrated a pattern of boundary placement that indicated over-compensation for liaison, suggesting that they had successfully acquired, but not fully constrained, rules about liaison.

This paper explores how theories on the relationship between language and domain-general cognitive capabilities might account for individual variation in second language learning. We investigated the acquisition of a morphophonological grammar paired with standardized tests of memory function. The language learned had simple and complex morphophonological patterns of word formation, which are hypothesized to correlate with standardized measures of procedural and declarative memory, respectively. The results show a significant amount of variation in learning success is accounted for by these measures of memory in accordance with the hypothesis. These findings help explain why some adults are able to learn a second language more easily than others while also advancing a model of second language learning motivated by linguistic theory.

Children with dyslexia often exhibit increased variability in sensory and cognitive aspects of hearing relative to typically developing peers. Assistive listening devices (classroom FM systems) may reduce auditory processing variability by enhancing acoustic clarity and attention. We assessed the impact of classroom FM system use for 1 year on auditory neurophysiology and reading skills in children with dyslexia. FM system use reduced the variability of subcortical responses to sound, and this improvement was linked to concomitant increases in reading and phonological awareness. Moreover, response consistency before FM system use predicted gains in phonological awareness. A matched control group of children with dyslexia attending the same schools who did not use the FM system did not show these effects. Assistive listening devices can improve the neural representation of speech and impact reading-related skills by enhancing acoustic clarity and attention, reducing variability in auditory processing.

This article presents a review of the effects of adverse conditions (ACs) on the perceptual, linguistic, cognitive, and neurophysiological mechanisms underlying speech recognition. The review starts with a classification of ACs based on their origin: Degradation at the source (production of a noncanonical signal), degradation during signal transmission (interfering signal or medium-induced impoverishment of the target signal), receiver limitations (peripheral, linguistic, cognitive). This is followed by a parallel, yet orthogonal classification of ACs based on the locus of their effect: Perceptual processes, mental representations, attention, and memory functions. We then review the added value that ACs provide for theories of speech recognition, with a focus on fundamental themes in psycholinguistics: Content and format of lexical representations, time-course of lexical access, word segmentation, feed-back in speech perception and recognition, lexicalsemantic integration, interface between the speech system and general cognition, neuroanatomical organisation of speech processing. We conclude by advocating an approach to speech recognition that includes rather than neutralises complex listening environments and individual differences.

The goal of the present study was to devise a means of representing languages in a perceptual similarity space based on their overall phonetic similarity. In Experiment 1, native English listeners performed a free classification task in which they grouped 17 diverse languages based on their perceived phonetic similarity. A similarity matrix of the grouping patterns was then submitted to clustering and multidimensional scaling analyses. In Experiment 2, an independent group of native English listeners sorted the group of 17 languages in terms of their distance from English. Experiment 3 repeated Experiment 2 with four groups of non-native English listeners: Dutch, Mandarin, Turkish and Korean listeners. Taken together, the results of these three experiments represent a step towards establishing an approach to assess the overall phonetic similarity of languages. This approach could potentially provide the basis for developing predictions regarding foreign-accented speech intelligibility for various listener groups, and regarding speech perception accuracy in the context of background noise in various languages.

The bulk of the work on non-native speech has focused on average differences between L1 and L2 speakers. However there is growing evidence that variability also plays an important role in distinguishing L1 from L2 speech. While some studies have demonstrated greater variability for non-native than native speech (e.g., Baese-Berk & Morrill, 2015; Wade et al., 2007), others have demonstrated that under some circumstances non-native speech maybe lessvariable and that variability in non-native speech may shift as a function of many factors, including task (Baese-Berk & Morrill, to appear; Baese-Berk, Morrill, & Bradlow, 2016) and L1-L2 pairing (Vaughn, Baese-Berk, & Idemaru, to appear). In this study, we ask how variability manifests in L1 and L2 speech by speakers from a variety of language backgrounds. Specifically, we ask whether a speaker whose L1 speaking rate is highly variable is also highly variable in their L2. We also ask whether variability in speaking rate in L1 or L2 differs as a function of task (e.g., read vs. spontaneous speech) and complexity of the task (e.g., more or less complicated reading passages). The results of this study will inform our understanding of the myriad complex factors that influence non-native speech. The bulk of the work on non-native speech has focused on average differences between L1 and L2 speakers. However there is growing evidence that variability also plays an important role in distinguishing L1 from L2 speech. While some studies have demonstrated greater variability for non-native than native speech (e.g., Baese-Berk & Morrill, 2015; Wade et al., 2007), others have demonstrated that under some circumstances non-native speech maybe lessvariable and that variability in non-native speech may shift as a function of many factors, including task (Baese-Berk & Morrill, to appear; Baese-Berk, Morrill, & Bradlow, 2016) and L1-L2 pairing (Vaughn, Baese-Berk, & Idemaru, to appear). In this study, we ask how variability manifests in L1 and L2 speech by speakers from a variety of language backgrounds. Specifically, we ask whether a speaker whose L1 speaking rate is highly variable is also highly variable in their L2. We also ask whether variability in speaking rate in L1 or L2 differs as a function of tas...