Rebecca E. Bieber

Purpose: Some bilinguals may exhibit lower performance when recognizing speech in noise (SiN) in their second language (L2) compared to monolinguals in their first language. Poorer performance has been found mostly for late bilinguals (L2 acquired after childhood) listening to sentences containing linguistic context and less so for simultaneous/early bilinguals (L2 acquired during childhood) and when testing context-free stimuli. However, most previous studies tested younger participants, meaning little is known about interactions with age; the purpose of this study was to address this gap. Method: Context-free SiN understanding was measured via the Modified Rhyme Test (MRT) in 3,803 young and middle-aged bilingual and monolingual adults (ages 18–57 years; 19.6% bilinguals, all L2 English) with normal to near-normal hearing. Bilingual adults included simultaneous ( n = 462), early ( n = 185), and late ( n = 97) bilinguals. Performance on the MRT was measured with both accuracy and response time. A self-reported measure of current English use was also collected for bilinguals to evaluate its impact on MRT performance. Results: Current age impacted MRT accuracy scores differently for each listener group. Relative to monolinguals, simultaneous and early bilinguals showed decreased performance with older age. Response times slowed with increasing current age at similar rates for all groups, despite faster overall response times for monolinguals. Among all bilingual listeners, greater current English language use predicted higher MRT accuracy. For simultaneous bilinguals, greater English use was associated with faster response times. Conclusions: SiN outcomes in bilingual adults are impacted by age at time of testing and by fixed features of their language history (i.e., age of acquisition) as well as language practices, which can shift over time (i.e., current language use). Results support routine querying of language history and use in the audiology clinic. Supplemental Material: https://doi.org/10.23641/asha.28405430

Purpose: Some bilinguals may exhibit lower performance when understanding speech in noise (SIN) in their second language (L2) compared to monolinguals in their first language. Poorer performance has been found mostly for late bilinguals (L2 acquired after childhood) listening to sentences containing linguistic context, and less so for simultaneous/early bilinguals (L2 acquired during childhood) and when testing context-free stimuli. However, most previous studies tested younger participants, meaning little is known about interactions with age; the purpose of this study was to address this gap.Method: Context-free SIN understanding was measured via the Modified Rhyme Test (MRT) in 3836 young and middle-aged bilingual and monolingual adults (ages 18–57; 19.5% bilinguals, all L2 English) with normal to near-normal hearing. Bilingual adults included simultaneous (n = 466), early (n = 185), and late (n = 97) bilinguals. Performance on the MRT was measured with both accuracy and response time. A self-reported measure of current English use was also collected for bilinguals to evaluate its impact on MRT performance.Results: Age impacted MRT accuracy scores differently for each listener group. Relative to monolinguals, simultaneous and early bilinguals showed decreased performance with older age. Response times slowed with older age at similar rates for all groups, despite faster overall response times for monolinguals. Among all bilingual listeners, greater current English language use predicted higher MRT accuracy. For simultaneous bilinguals, greater English use was associated with faster response times. Conclusions: Speech-in-noise outcomes in bilingual adults are impacted not only by fixed features of their language history (i.e. age of acquisition) but also by language practices which can shift over time (i.e. current language use), supporting routine querying of language history and use in the Audiology clinic.

Purpose: A corpus of English matrix sentences produced by 60 native and nonnative speakers of English was developed as part of a multinational coalition task group. This corpus was tested on a large cohort of U.S. Service members in order to examine the effects of talker nativeness, listener nativeness, masker type, and hearing sensitivity on speech recognition performance in this population. Method: A total of 1,939 U.S. Service members (ages 18–68 years) completed this closed-set listening task, including 430 women and 110 nonnative English speakers. Stimuli were produced by native and nonnative speakers of English and were presented in speech-shaped noise and multitalker babble. Keyword recognition accuracy and response times were analyzed. Results: General(ized) linear mixed-effects regression models found that, on the whole, speech recognition performance was lower for listeners who identified as nonnative speakers of English and when listening to speech produced by nonnative speakers of English. Talker and listener effects were more pronounced when listening in a babble masker than in a speech-shaped noise masker. Response times varied as a function of recognition score, with longest response times found for intermediate levels of performance. Conclusions: This study found additive effects of talker and listener nonnativeness when listening to speech in background noise. These effects were present in both accuracy and response time measures. No multiplicative effects of talker and listener language background were found. There was little evidence of a negative interaction between talker nonnativeness and hearing impairment, suggesting that these factors may have redundant effects on speech recognition. Supplemental Material: https://doi.org/10.23641/asha.26060191

Purpose: The purpose of this study was to explore potential differences in suprathreshold auditory function among native and nonnative speakers of English as a function of age. Method: Retrospective analyses were performed on three large data sets containing suprathreshold auditory tests completed by 5,572 participants who were self-identified native and nonnative speakers of English between the ages of 18–65 years, including a binaural tone detection test, a digit identification test, and a sentence recognition test. Results: The analyses show a significant interaction between increasing age and participant group on tests involving speech-based stimuli (digit strings, sentences) but not on the binaural tone detection test. For both speech tests, differences in speech recognition emerged between groups during early adulthood, and increasing age had a more negative impact on word recognition for nonnative compared to native participants. Age-related declines in performance were 2.9 times faster for digit strings and 3.3 times faster for sentences for nonnative participants compared to native participants. Conclusions: This set of analyses extends the existing literature by examining interactions between aging and self-identified native English speaker status in several auditory domains in a cohort of adults spanning young adulthood through middle age. The finding that older nonnative English speakers in this age cohort may have greater-than-expected deficits on speech-in-noise perception may have clinical implications on how these individuals should be diagnosed and treated for hearing difficulties.

Listeners can rapidly adapt to English speech produced by non-native speakers of English with unfamiliar accents. Prior work has shown that the type and number of talkers contained within a stimulus set may impact rate and magnitude of learning, as well as any generalization of learning. However, findings across the literature have been inconsistent, with relatively little study of these effects in populations of older listeners. In this study, adaptation and generalization to unfamiliar talkers with familiar and unfamiliar accents are studied in younger normal-hearing adults and older adults with and without hearing loss. Rate and magnitude of adaptation are modelled using both generalized linear mixed effects regression and generalized additive mixed effects modelling. Rate and magnitude of adaptation were not impacted by increasing the number of talkers and/or varying the consistency of non-native English accents across talkers. Increasing the number of talkers did strengthen generalization of learning for a talker with a familiar non-native accent, but not for an unfamiliar accent. Aging alone did not diminish adaptation or generalization. These findings support prior evidence of a limited benefit for talker variability in facilitating generalization of learning for non-native accented speech, and extend the findings to older adults.

Purpose: The purpose of this study was to explore potential differences in suprathreshold auditory function among native and nonnative speakers of English as a function of age. Method: Retrospective analyses were performed on three large datasets containing suprathreshold auditory tasks completed by 5572 participants who were self-identified native and nonnative speakers of English between the ages of 18–65, including a binaural tone detection task, a digit identification task, and a sentence recognition task.Results: The analyses show a significant interaction between increasing age and participant group on tasks involving speech-based stimuli (digit strings, sentences) but not on the binaural tone detection task. For both speech tasks, differences in speech recognition emerged between groups during early adulthood and increasing age had a more negative impact on word recognition for nonnative compared to native participants. Age-related declines in performance were 2.9 times faster for digit strings and 3.3 times faster for sentences for nonnative participants compared to native participants. Conclusions: This set of analyses extends the existing literature by examining interactions between aging and language background in several auditory domains in a cohort of adults spanning young adulthood through middle age. The finding that older nonnative English speakers in this age cohort may have greater than expected deficits on speech-in-noise perception may have clinical implications on how these individuals should be diagnosed and treated for hearing difficulties.

Non-native, accented speech spoken by unfamiliar talkers can be challenging to recognize, but rapid improvements in perception are often observed after a short period of exposure. However, it is not clear whether these improvements are retained over multiple sessions. Stimulus variability facilitates learning for non-native speech, so it is possible it may also induce increased retention of learning for speech produced with an unfamiliar accent. In this paper, we conduct a retrospective analysis of a dataset well suited to examine learning of non-native English speech on both a within-session and across-session basis. During data collection, participants completed a protocol involving recognition of matrix sentences recorded by native and non-native talkers with different first languages. Listeners completed the protocol in a self-paced approach, including 15 blocks of 50 trials over 4–7 days, separated by an average of 1–2 days. Learning was strongest within the first day, and improvements were retained at subsequent test sessions. The pace of learning was faster for stimuli produced by native speakers of English as compared to non-native English speakers.

When speech is degraded or challenging to recognize, young adult listeners with normal hearing are able to quickly adapt, improving their recognition of the speech over a short period of time. This rapid adaptation is robust, but the factors influencing rate, magnitude, and generalization of improvement have not been fully described. Two factors of interest are lexico-semantic information and talker and accent variability; lexico-semantic information promotes perceptual learning for acoustically ambiguous speech, while talker and accent variability are beneficial for generalization of learning. In the present study, rate and magnitude of adaptation were measured for speech varying in level of semantic context, and in the type and number of talkers. Generalization of learning to an unfamiliar talker was also assessed. Results indicate that rate of rapid adaptation was slowed for semantically anomalous sentences, as compared to semantically intact or topic-grouped sentences; however, generalization was seen in the anomalous conditions. Magnitude of adaptation was greater for non-native as compared to native talker conditions, with no difference between single and multiple non-native talker conditions. These findings indicate that the previously documented benefit of lexical information in supporting rapid adaptation is not enhanced by the addition of supra-sentence context.

Older adults often report difficulty understanding speech produced by non-native talkers. These listeners can achieve rapid adaptation to non-native speech, but few studies have assessed auditory training protocols to improve non-native speech recognition in older adults. In this study, a word-level training paradigm was employed, targeting improved recognition of Spanish-accented English. Younger and older adults were trained on Spanish-accented monosyllabic word pairs containing four phonemic contrasts (initial s/z, initial f/v, final b/p, final d/t) produced in English by multiple male native Spanish speakers. Listeners completed pre-testing, training, and post-testing over two sessions. Statistical methods, such as growth curve modeling and generalized additive mixed models, were employed to describe the patterns of rapid adaptation and how they varied between listener groups and phonemic contrasts. While the training protocol failed to elicit post-test improvements for recognition of Spanish-accented speech, examination of listeners' performance during the pre-testing period showed patterns of rapid adaptation that differed, depending on the nature of the phonemes to be learned and the listener group. Normal-hearing younger and older adults showed a faster rate of adaptation for non-native stimuli that were more nativelike in their productions, while older adults with hearing impairment did not realize this benefit.