Does race impact speech perception? An account of accented speech in two different multilingual locales

How does the human brain process noisy speech in real life? Insights from the second-person neuroscience perspective

Comprehending speech with the existence of background noise is of great importance for human life. In the past decades, a large number of psychological, cognitive and neuroscientific research has explored the neurocognitive mechanisms of speech-in-noise comprehension. However, as limited by the low ecological validity of the speech stimuli and the experimental paradigm, as well as the inadequate attention on the high-order linguistic and extralinguistic processes, there remains much unknown about how the brain processes noisy speech in real-life scenarios. A recently emerging approach, i.e., the second-person neuroscience approach, provides a novel conceptual framework. It measures both of the speaker's and the listener's neural activities, and estimates the speaker-listener neural coupling with regarding of the speaker's production-related neural activity as a standardized reference. The second-person approach not only promotes the use of naturalistic speech but also allows for free communication between speaker and listener as in a close-to-life context. In this review, we first briefly review the previous discoveries about how the brain processes speech in noise; then, we introduce the principles and advantages of the second-person neuroscience approach and discuss its implications to unravel the linguistic and extralinguistic processes during speech-in-noise comprehension; finally, we conclude by proposing some critical issues and calls for more research interests in the second-person approach, which would further extend the present knowledge about how people comprehend speech in noise.

Receptive vocabulary predicts multilinguals' recognition skills in adverse listening conditions

Adverse listening conditions are known to affect bilingual listeners' intelligibility scores more than those of monolingual listeners. To advance theoretical understanding of the mechanisms underpinning bilinguals' challenges in adverse listening conditions, vocabulary size and language entropy are compared as predictors in a sentence transcription task with a heterogeneous multilingual population representative of a speech community. Adverse listening was induced through noise type, bandwidth manipulations, and sentences varying in their semantic predictability. Overall, the results generally confirm anticipated patterns with respect to sentence type, noise masking, and bandwidth. Listeners show better comprehension of semantically coherent utterances without masking and with a full spectrum. Crucially, listeners with larger receptive vocabularies and lower language entropy, a measure of the predictability of one's language use, showed improved performance in adverse listening conditions. Vocabulary size had a substantially larger effect size, indicating that vocabulary size has more impact on performance in adverse listening conditions than bilingual language use. These results suggest that the mechanism behind the bilingual disadvantage in adverse listening conditions may be rooted in bilinguals' smaller language-specific receptive vocabularies, offering a harmonious explanation for challenges in adverse listening conditions experienced by monolinguals and multilinguals.

Exploring effects of social information on talker-independent accent adaptation

The present study examined whether race information about speakers can promote rapid and generalizable perceptual adaptation to second-language accent. First-language English listeners were presented with Cantonese-accented English sentences in speech-shaped noise during a training session with three intermixed talkers, followed by a test session with a novel (i.e., fourth) talker. Participants were assigned to view either three East Asian or three White faces during training, corresponding to each speaker. Results indicated no effect of the social priming manipulation on the training or test sessions, although both groups performed better at test than a control group.

Visual information affects adaptation to novel talkers: Ethnicity-specific and ethnicity-independent learning of L2-accented speech

Prior work demonstrates that exposure to speakers of the same accent facilitates comprehension of a novel talker with the same accent (accent-specific learning). Moreover, exposure to speakers of multiple different accents enhances understanding of a talker with a novel accent (accent-independent learning). Although bottom-up acoustic information about accent constrains adaptation to novel talkers, the effect of top-down social information remains unclear. The current study examined effects of apparent ethnicity on adaptation to novel L2-accented ("non-native") talkers while keeping bottom-up information constant. Native English listeners transcribed sentences in noise for three Mandarin-accented English speakers and then a fourth (novel) Mandarin-accented English speaker. Transcription accuracy of the novel talker improves when: all speakers are presented with east Asian faces (ethnicity-specific learning); the exposure speakers are paired with different, non-east Asian ethnicities and the novel talker has an east Asian face (ethnicity-independent learning). However, accuracy does not improve when all speakers have White faces or when the exposure speakers have White faces and the test talker has an east Asian face. This study demonstrates that apparent ethnicity affects adaptation to novel L2-accented talkers, thus underscoring the importance of social expectations in perceptual learning and cross-talker generalization.

Social Priming: Exploring the Effects of Speaker Race and Ethnicity on Perception of Second Language Accents

Listeners use more than just acoustic information when processing speech. Social information, such as a speaker's perceived race or ethnicity, can also affect the processing of the speech signal, in some cases facilitating perception ("social priming"). We aimed to replicate and extend this line of inquiry, examining effects of multiple social primes (i.e., a Middle Eastern, White, or East Asian face, or a control silhouette image) on the perception of Mandarin Chinese-accented English and Arabic-accented English. By including uncommon priming combinations (e.g., a Middle Eastern prime for a Mandarin accent), we aimed to test the specificity of social primes: For example, can a Middle Eastern face facilitate perception of both Arabic-accented English and Mandarin-accented English? Contrary to our predictions, our results indicated no facilitative social priming effects for either of the second language (L2) accents. Results for our examination of specificity were mixed. Trends in the data indicated that the combination of an East Asian prime with Arabic accent resulted in lower accuracy as compared with a White prime, but the combination of a Middle Eastern prime with a Mandarin accent did not (and may have actually benefited listeners to some degree). We conclude that the specificity of priming effects may depend on listeners' level of familiarity with a given accent and/or racial/ethnic group and that the mixed outcomes in the current work motivate further inquiries to determine whether social priming effects for L2-accented speech may be smaller than previously hypothesized and/or highly dependent on listener experience.

Foreign Accented-Speech and Perceptions of Confidence and Intelligence

The purpose of the current study is to explore listeners' perception of accented speech in terms of confidence and intelligence. To this end, three groups of listeners were asked to rate speakers of English with various accent strengths based on a 9-point scale in terms of accent magnitude, confidence and intelligence. Results show that the two Jordanian listener groups, unlike the English listeners, reacted similarly toward Jordanian-accented speakers of English. Overall, the three groups tended to link accentedness with perceptions of confidence and intelligence. The findings of this study have significant implications for advocating a tolerant attitude toward speakers of English as a foreign language in the fields of education, employment opportunities, and social justice. It is suggested that stereotyping speakers as inferior in terms of qualities such as confidence and intelligence reflects established listener's bias rather than lack of speaker's intelligibility.

Moving away from deficiency models: Gradiency in bilingual speech categorization

For much of its history, categorical perception was treated as a foundational theory of speech perception, which suggested that quasi-discrete categorization was a goal of speech perception. This had a profound impact on bilingualism research which adopted similar tasks to use as measures of nativeness or native-like processing, implicitly assuming that any deviation from discreteness was a deficit. This is particularly problematic for listeners like heritage speakers whose language proficiency, both in their heritage language and their majority language, is questioned. However, we now know that in the monolingual listener, speech perception is gradient and listeners use this gradiency to adjust subphonetic details, recover from ambiguity, and aid learning and adaptation. This calls for new theoretical and methodological approaches to bilingualism. We present the Visual Analogue Scaling task which avoids the discrete and binary assumptions of categorical perception and can capture gradiency more precisely than other measures. Our goal is to provide bilingualism researchers new conceptual and empirical tools that can help examine speech categorization in different bilingual communities without the necessity of forcing their speech categorization into discrete units and without assuming a deficit model.

Adaptation to Social-Linguistic Associations in Audio-Visual Speech

Listeners entertain hypotheses about how social characteristics affect a speaker’s pronunciation. While some of these hypotheses may be representative of a demographic, thus facilitating spoken language processing, others may be erroneous stereotypes that impede comprehension. As a case in point, listeners’ stereotypes of language and ethnicity pairings in varieties of North American English can improve intelligibility and comprehension, or hinder these processes. Using audio-visual speech this study examines how listeners adapt to speech in noise from four speakers who are representative of selected accent-ethnicity associations in the local speech community: an Asian English-L1 speaker, a white English-L1 speaker, an Asian English-L2 speaker, and a white English-L2 speaker. The results suggest congruent accent-ethnicity associations facilitate adaptation, and that the mainstream local accent is associated with a more diverse speech community.