Children's comprehension of unfamiliar regional accents: a preliminary investigation

Shared social groups or shared experiences? The effect of shared knowledge on children's perspective-taking

Although the ability to consider others' visual perspectives to interpret ambiguous communication emerges during childhood, people sometimes fail to attend to their partner's perspective. Two studies investigated whether 4- to 6-year-olds show a "closeness-communication bias" in their consideration of a partner's perspective in a communication task. Participants played a game that required them to take their partner's visual perspective in order to interpret an ambiguous instruction. If children, like adults, perform worse when they overestimate the extent to which their perspective is aligned with that of a partner, then they should make more perspective-taking errors when interacting with a socially close partner compared with a more socially distant partner. In Study 1, social closeness was based on belonging to the same social group. In Study 2, social closeness was based on caregiving, a long-standing social relationship with a close kinship bond. Although social group membership did not affect children's consideration of their partner's perspective, children did make more perspective-taking errors when interacting with a close caregiver compared with a novel experimenter. These findings suggest that close personal relationships may be more likely to lead children to overestimate perspective alignment and hinder children's perspective-taking than shared social group membership, and they highlight important questions about the mechanisms underlying the effects of partner characteristics in perspective-taking tasks.

Perceptual flexibility in word learning: Preschoolers learn words with speech sound variability

Children's language input is rife with acoustic variability. Much of this variability may facilitate learning by highlighting unvarying, criterial speech attributes. But in many cases, learners experience variation in those criterial attributes themselves, as when hearing speakers with different accents. How flexible are children in the face of this variability? The current study taught 3-5-year-olds new words containing speech-sound variability: a single picture might be labeled both deev and teev. After learning, children's knowledge was tested by presenting two pictures and asking them to point to one. Picture-pointing accuracy and eye movements were tracked. While children pointed less accurately and looked less rapidly to dual-label than single-label words, they robustly exceeded chance. Performance was weaker when children learned two distinct labels, such as vayfe and fosh, for a single object. Findings suggest moderate learning even with speech-sound variability. One implication is that neural representations of speech contain rich gradient information.

How pronunciation distance impacts word recognition in children and adults

Although unfamiliar accents can pose word identification challenges for children and adults, few studies have directly compared perception of multiple nonnative and regional accents or quantified how the extent of deviation from the ambient accent impacts word identification accuracy across development. To address these gaps, 5- to 7-year-old children's and adults' word identification accuracy with native (Midland American, British, Scottish), nonnative (German-, Mandarin-, Japanese-accented English) and bilingual (Hindi-English) varieties (one talker per accent) was tested in quiet and noise. Talkers' pronunciation distance from the ambient dialect was quantified at the phoneme level using a Levenshtein algorithm adaptation. Whereas performance was worse on all non-ambient dialects than the ambient one, there were only interactions between talker and age (child vs adult or across age for the children) for a subset of talkers, which did not fall along the native/nonnative divide. Levenshtein distances significantly predicted word recognition accuracy for adults and children in both listening environments with similar impacts in quiet. In noise, children had more difficulty overcoming pronunciations that substantially deviated from ambient dialect norms than adults. Future work should continue investigating how pronunciation distance impacts word recognition accuracy by incorporating distance metrics at other levels of analysis (e.g., phonetic, suprasegmental).

Impacts of acoustic-phonetic variability on perceptual development for spoken language: A review

This article reviews research on when acoustic-phonetic variability facilitates, inhibits, or does not impact perceptual development for spoken language, to illuminate mechanisms by which variability aids learning of language sound patterns. We first summarize structures and sources of variability. We next present proposed mechanisms to account for how and why variability impacts learning. Finally, we review effects of variability in the domains of speech-sound category and pattern learning; word-form recognition and word learning; and accent processing. Variability can be helpful, harmful, or neutral depending on the learner's age and learning objective. Irrelevant variability can facilitate children's learning, particularly for early learning of words and phonotactic rules. For speech-sound change detection and word-form recognition, children seem either unaffected or impaired by irrelevant variability. At the same time, inclusion of variability in training can aid generalization. Variability between accents may slow learning-but with the longer-term benefits of improved comprehension of multiple accents. By highlighting accent as a form of acoustic-phonetic variability and considering impacts of dialect prestige on children's learning, we hope to contribute to a better understanding of how exposure to multiple accents impacts language development and may have implications for literacy development. This article is categorized under: Linguistics > Language Acquisition Psychology > Language Psychology > Perception and Psychophysics.

Identification of Foreign-Accented Words in Preschoolers With and Without Speech Sound Disorders

Purpose The aim of this study was to investigate the ability of preschoolers with speech sound disorder (SSD) and with typical speech and language development (TD) to understand foreign-accented words, providing a window into the quality of their underlying phonological representations. We also investigated the relationship between vocabulary skills and the ability to identify words that are frequent and have few neighbors (lexically easy words) and words that are less frequent and have many neighbors (lexically hard words). Method Thirty-two monolingual English-speaking children (16 with SSD, 16 with TD), ages 4 and 5 years, completed standardized speech and language tests and a two-alternative forced-choice word identification task of English words produced by a native English speaker and a native Korean speaker. Results Children with SSD had more difficulty identifying words produced by both talkers than children with TD and showed a larger difficulty identifying Korean-accented words. Both groups of children identified lexically easy words more accurately than lexically hard words, although this difference was not significant when including receptive vocabulary skills in the analysis. Identification of lexically hard words, both those produced by the native English speaker and the nonnative English speaker, increased with vocabulary size. Conclusion Considering the performance of the children with SSD under ideal listening conditions in this study, we can assume that, as a group, children with SSD may experience greater difficulty identifying foreign-accented words in environments with background noise.

Developmental sociolinguistics: Children's acquisition of language variation

Developmental sociolinguistics is a rapidly evolving interdisciplinary framework that builds upon theoretical and methodological contributions from multiple disciplines (i.e., sociolinguistics, language acquisition, the speech sciences, developmental psychology, and psycholinguistics). A core assumption of this framework is that language is by its very nature variable, and that much of this variability is informative, as it is (probabilistically) governed by a variety of factors-including linguistic context, social or cultural context, the relationship between speaker and addressee, a language user's geographic origin, and a language user's gender identity. It is becoming increasingly clear that consideration of these factors is absolutely essential to developing realistic and ecologically valid models of language development. Given the central importance of language in our social world, a more complete understanding of early social development will also require a deeper understanding of when and how language variation influences children's social inferences and behavior. As the cross-pollination between formerly disparate fields continues, we anticipate a paradigm shift in the way many language researchers conceptualize the challenge of early acquisition. This article is categorized under: Linguistics > Linguistic Theory Linguistics > Language Acquisition Neuroscience > Development Psychology > Language.

Effects of Language Background on the Development of Sociolinguistic Awareness: The Perception of Accent Variation in Monolingual and Multilingual 5- to 7-Year-Old Children

As a result of complex international migration patterns, listeners in large urban centres such as London, UK, likely encounter large amounts of variation in spoken language. However, although dealing with variation is crucial to communication, relatively little is known about how the ability to do this develops. Still less is known about how this might be affected by language background. The current study investigates whether early experience with variation, specifically growing up bilingually in London, affects accent categorization. Sixty children (30 monolingual, 30 bilingual) aged 5-7 years, were tested in their ability to comprehend and categorize talkers in 2 out of 3 accents: a home, unfamiliar regional and unfamiliar foreign-accented variety. All children demonstrated high, above-chance performance in the comprehension task, but language background significantly affected the children's ability to categorize talkers. Bilinguals were able to categorize talkers in all accent conditions, but although all children were able to understand the talkers, monolingual children were only able to categorize talkers in the home-foreign accent condition. Overall, the results are consistent with an approach in which gradient representations of accent variation emerge alongside an understanding of how variation is used meaningfully within a child's environment.

Processing of unfamiliar accents in monolingual and bilingual children: effects of type and amount of accent experience

Substantial individual differences exist in regard to type and amount of experience with variable speech resulting from foreign or regional accents. Whereas prior experience helps with processing familiar accents, research on how experience with accented speech affects processing of unfamiliar accents is inconclusive, ranging from perceptual benefits to processing disadvantages. We examined how experience with accented speech modulates mono- and bilingual children's (mean age: 9;10) ease of speech comprehension for two unfamiliar accents in German, one foreign and one regional. More experience with regional accents helped children repeat sentences correctly in the regional condition and in the standard condition. More experience with foreign accents did not help in either accent condition. The results suggest that type and amount of accent experience co-determine processing ease of accented speech.

Shhh… I Need Quiet! Children's Understanding of American, British, and Japanese-accented English Speakers

Children's ability to understand speakers with a wide range of dialects and accents is essential for efficient language development and communication in a global society. Here, the impact of regional dialect and foreign-accent variability on children's speech understanding was evaluated in both quiet and noisy conditions. Five- to seven-year-old children ( n = 90) and adults ( n = 96) repeated sentences produced by three speakers with different accents-American English, British English, and Japanese-accented English-in quiet or noisy conditions. Adults had no difficulty understanding any speaker in quiet conditions. Their performance declined for the nonnative speaker with a moderate amount of noise; their performance only substantially declined for the British English speaker (i.e., below 93% correct) when their understanding of the American English speaker was also impeded. In contrast, although children showed accurate word recognition for the American and British English speakers in quiet conditions, they had difficulty understanding the nonnative speaker even under ideal listening conditions. With a moderate amount of noise, their perception of British English speech declined substantially and their ability to understand the nonnative speaker was particularly poor. These results suggest that although school-aged children can understand unfamiliar native dialects under ideal listening conditions, their ability to recognize words in these dialects may be highly susceptible to the influence of environmental degradation. Fully adult-like word identification for speakers with unfamiliar accents and dialects may exhibit a protracted developmental trajectory.

Development of unfamiliar accent comprehension continues through adolescence

School-age children's understanding of unfamiliar accents is not adult-like and the age at which this ability fully matures is unknown. To address this gap, eight- to fifteen-year-old children's (n = 74) understanding of native- and non-native-accented sentences in quiet and noise was assessed. Children's performance was adult-like by eleven to twelve years for the native accent in noise and by fourteen to fifteen years for the non-native accent in quiet. However, fourteen- to fifteen-year old's performance was not adult-like for the non-native accent in noise. Thus, adult-like comprehension of unfamiliar accents may require greater exposure to linguistic variability or additional cognitive-linguistic growth.

Investigating the effect of regional native accents on sentence comprehension in children with language impairment

PURPOSE

Research has shown that accent variation can affect typically developing (TD) children's understanding of language, as well as that of children with speech difficulties, neuro-typical adults and those with aphasia and dementia. This study aims to investigate the effect of regional native accents on sentence comprehension in children with language impairment (LI), an area not previously explored.

METHOD

Forty-three children with LI (mean age 6.04) and forty-five younger TD children (mean age 4.10), matched on a measure of sentence comprehension, completed a sentence comprehension task spoken in three regional accents. Instructions were spoken in the children's local Irish accent, a neutral-Irish accent and an unfamiliar Northern-Irish (NI) accent. Instructions were adapted from the Token Test and were matched on syllable length and complexity.

RESULT

The two groups performed similarly overall on the task. Children had significantly greater difficulty understanding instructions spoken in the NI accent than in either of the other two accents. The ability to process accent variation was significantly associated with receptive language and phonological short term memory ability.

CONCLUSIONS

Variation in regional accents may be negatively impacting the performance of children on language comprehension assessments. Potential effects on diagnostic or clinical decisions will require further exploration.

The effect of different speaker accents on sentence comprehension in children with speech sound disorder

There is substantial evidence that a speaker's accent, specifically an unfamiliar accent, can affect the listener's comprehension. In general, this effect holds true for both adults and children as well as those with typical and impaired language. Previous studies have investigated the effect of different accents on individuals with language disorders, but children with speech sound disorders (SSDs) have received little attention. The current study aims to learn more about the ability of children with SSD to process different speaker accents. Fifteen children with SSD aged between 4;01 and 5;11 years, and 16 typically developing children matched on language ability, age, socioeconomic status, gender and cognitive ability participated in the current study. A sentence comprehension task was carried out with each child, requiring them to follow instructions of increasing length spoken in three different accents - (i) a local Irish (Cork) accent, (ii) a regional North American accent and (iii) a non-native Indian English accent. Results showed no significant group difference and speaker accent did not significantly impact children's performance on the task. The results are discussed in relation to factors that influence accent comprehension, and their implications for children's underlying phonological representations.

Processing and Comprehension of Accented Speech by Monolingual and Bilingual Children

This study tested the effect of Spanish-accented speech on sentence comprehension in children with different degrees of Spanish experience. The hypothesis was that earlier acquisition of Spanish would be associated with enhanced comprehension of Spanish-accented speech. Three groups of 5-6 year old children were tested: monolingual English-speaking children, simultaneous Spanish-English bilingual children and early English-Spanish bilingual children. The children completed a semantic judgment task in English on semantically meaningful and nonsensical sentences produced by a native English speaker and a native Spanish speaker characterized by a strong Spanish accent. All children were slower to respond to foreign accented speech, independent of language background. Monolingual and early bilingual children showed reduced comprehension accuracy of accented speech, but only for nonsensical sentences. Simultaneous bilingual children performed similarly to other groups for meaningful contexts, but were not as strongly affected by accent for nonsensical contexts. Together, the findings suggest that children's language background has only a minor influence on processing of accented speech.

Exposure to multiple accents supports infants' understanding of novel accents

Accented speech poses a challenge for listeners, particularly those with limited knowledge of their language. In a series of studies, we explored the possibility that experience with variability, specifically the variability provided by multiple accents, would facilitate infants' comprehension of speech produced with an unfamiliar accent. 15- and 18-month-old American-English learning infants were exposed to brief passages of multi-talker speech and subsequently tested on their ability to distinguish between real, familiar words and nonsense words, produced in either their native accent or an unfamiliar (British) accent. Exposure passages were produced in a familiar (American) accent, a single unfamiliar (British) accent or a variety of novel accents (Australian, Southern, Indian). While 15-month-olds successfully recognized real words spoken in a familiar accent, they never demonstrated comprehension of English words produced in the unfamiliar accent. 18-month-olds also failed to recognize English words spoken in the unfamiliar accent after exposure to the familiar or single unfamiliar accent. However, they succeeded after exposure to multiple unfamiliar accents, suggesting that as they get older, infants are better able to exploit the cues provided by variable speech. Increased variability across multiple dimensions can be advantageous for young listeners.

Perception of Nonnative-accented Sentences by 5- to 8-Year-olds and Adults: The Role of Phonological Processing Skills

To acquire language and successfully communicate in multicultural and multilingual societies, children must learn to understand speakers with various accents and dialects. This study investigated adults' and 5- to 8-year-old children's perception of native- and nonnative-accented English sentences in noise. Participants' phonological memory and phonological awareness were assessed to investigate factors associated with individual differences in word recognition. Although both adults and children performed less accurately with nonnative talkers than native talkers, children showed greater performance decrements. Further, phonological memory was more closely tied to perception of native talkers whereas phonological awareness was more closely related to perception of nonnative talkers. These results suggest that the ability to recognize words produced in unfamiliar accents continues to develop beyond the early school-age years. Additionally, the linguistic skills most related to word recognition in adverse listening conditions may differ depending on the source of the challenge (i.e., noise, talker, or a combination).

Vocabulary size and auditory word recognition in preschool children

Recognizing familiar words quickly and accurately facilitates learning new words, as well as other aspects of language acquisition. This study used the visual world paradigm with semantic and phonological competitors to study lexical processing efficiency in 2-5 year-old children. Experiment 1 found this paradigm was sensitive to vocabulary-size differences. Experiment 2 included a more diverse group of children who were tested in their native dialect (either African American English or Mainstream American English). No effect of stimulus dialect was observed,. Results showed that vocabulary size was a better predictor of eye gaze patterns than maternal education, but that maternal education level had a moderating effect; as maternal education level increased, vocabulary size was less predictive of lexical processing efficiency.

Children's Use of Semantic Context in Perception of Foreign-Accented Speech

PURPOSE

The purpose of this study is to evaluate children's use of semantic context to facilitate foreign-accented word recognition in noise.

METHOD

Monolingual American English speaking 5- to 7-year-olds (n = 168) repeated either Mandarin- or American English-accented sentences in babble, half of which contained final words that were highly predictable from context. The same final words were presented in the low- and high-predictability sentences.

RESULTS

Word recognition scores were better in the high- than low-predictability contexts. Scores improved with age and were higher for the native than the Mandarin accent. The oldest children saw the greatest benefit from context; however, context benefit was similar regardless of speaker accent.

CONCLUSION

Despite significant acoustic-phonetic deviations from native norms, young children capitalize on contextual cues when presented with foreign-accented speech. Implications for spoken word recognition in children with speech, language, and hearing differences are discussed.

Glasgow Gloom or Leeds Glue? Dialect-Specific Vowel Duration Constrains Lexical Segmentation and Access

Timing cues are important in many aspects of speech processing, fromidentifying segments to locating word and phrase boundaries. They vary across accents, yet representation and processing of this variation are poorly understood. We investigated whether an accent difference in vowel duration affects lexical segmentation and access. In Glasgow English (GE), /i u e o/ are shorter than in Leeds English (LE), especially for /i u/ before voiced stops and nasals. In a word-spotting experiment, GE and LE participants heard nonsense sequences (e.g. pobegloomezh) containing embedded words (gloom, glue), with segmental qualities intermediate between GE and LE. Critical vowel durations were manipulated according to accent (GE-appropriate vowels shorter than LE-appropriate ones) and phonological context (vowels shortest before voiceless stops < voiced stops/nasals < voiced fricatives). GE participants generally spotted words like gloom more accurately with GE-appropriate than LE-appropriate vowels. LE participants were less accurate than GE participants to spot words like gloom with GE-appropriate vowels, but more likely to spot embeddings like glue. These results were broadly as predicted based on the accent differences, but depended less than expected on the accent-specific phonological constraints. We discuss theoretical implications regarding the representation of duration and the time course of lexical access.

Children's comprehension of an unfamiliar speaker accent: a review

BACKGROUND

The effect of speaker accent on listeners' comprehension has become a key focus of research given the increasing cultural diversity of society and the increased likelihood of an individual encountering a clinician with an unfamiliar accent.

AIMS

To review the studies exploring the effect of an unfamiliar accent on language comprehension in typically developing (TD) children and in children with speech and language difficulties. This review provides a methodological analysis of the relevant studies by exploring the challenges facing this field of research and highlighting the current gaps in the literature.

METHODS & PROCEDURES

A total of nine studies were identified using a systematic search and organized under studies investigating the effect of speaker accent on language comprehension in (1) TD children and (2) children with speech and/or language difficulties.

MAIN CONTRIBUTION

This review synthesizes the evidence that an unfamiliar speaker accent may lead to a breakdown in language comprehension in TD children and in children with speech difficulties. Moreover, it exposes the inconsistencies found in this field of research and highlights the lack of studies investigating the effect of speaker accent in children with language deficits.

CONCLUSIONS & IMPLICATIONS

Overall, research points towards a developmental trend in children's ability to comprehend accent-related variations in speech. Vocabulary size, language exposure, exposure to different accents and adequate processing resources (e.g. attention) seem to play a key role in children's ability to understand unfamiliar accents. This review uncovered some inconsistencies in the literature that highlight the methodological issues that must be considered when conducting research in this field. It explores how such issues may be controlled in order to increase the validity and reliability of future research. Key clinical implications are also discussed.

Effects of contextual support on preschoolers' accented speech comprehension

Young children often hear speech in unfamiliar accents, but relatively little research characterizes their comprehension capacity. The current study tested preschoolers' comprehension of familiar-accented versus unfamiliar-accented speech with varying levels of contextual support from sentence frames (full sentences vs. isolated words) and from visual context (four salient pictured alternatives vs. the absence of salient visual referents). The familiar accent advantage was more robust when visual context was absent, suggesting that previous findings of good accent comprehension in infants and young children may result from ceiling effects in easier tasks (e.g., picture fixation, picture selection) relative to the more difficult tasks often used with older children and adults. In contrast to prior work on mispronunciations, where most errors were novel object responses, children in the current study did not select novel object referents above chance levels. This suggests that some property of accented speech may dissuade children from inferring that an unrecognized familiar-but-accented word has a novel referent. Finally, children showed detectable accent processing difficulty despite presumed incidental community exposure. Results suggest that preschoolers' accented speech comprehension is still developing, consistent with theories of protracted development of speech processing.

Early speech perception in Mandarin-speaking children at one-year post cochlear implantation

PURPOSE

The aim in this study was to examine early speech perception outcomes in Mandarin-speaking children during the first year of cochlear implant (CI) use.

METHOD

A hierarchical early speech perception battery was administered to 80 children before and 3, 6, and 12 months after implantation. Demographic information was obtained to evaluate its relationship with these outcomes.

RESULTS

Regardless of dialect exposure and whether a hearing aid was trialed before implantation, implant recipients were able to attain similar pre-lingual auditory skills after 12 months of CI use. Children speaking Mandarin developed early Mandarin speech perception faster than those with greater exposure to other Chinese dialects. In addition, children with better pre-implant hearing levels and younger age at implantation attained significantly better speech perception scores after 12 months of CI use. Better pre-implant hearing levels and higher maternal education level were also associated with a significantly steeper growth in early speech perception ability.

CONCLUSIONS

Mandarin-speaking children with CIs are able to attain early speech perception results comparable to those of their English-speaking counterparts. In addition, consistent single language input via CI probably enhances early speech perception development at least during the first-year of CI use.

Children's perception of nonnative-accented sentences in noise and quiet

Adult listeners' word recognition is remarkably robust under a variety of adverse listening conditions. However, the combination of two simultaneous listening challenges (e.g., nonnative speaker in noise) can cause significant word recognition decrements. This study investigated how talker-related (native vs nonnative) and environment-related (noise vs quiet) adverse conditions impact children's and adults' word recognition. Five- and six-year-old children and adults identified sentences produced by one native and one nonnative talker in both quiet and noise-added conditions. Children's word recognition declined significantly more than adults' in conditions with one source of listening adversity (i.e., native speaker in noise or nonnative speaker in quiet). Children's performance when the listening challenges were combined (nonnative talker in noise) was particularly poor. Immature speech-in-noise perception may be a result of children's difficulties with signal segregation or selective attention. In contrast, the explanation for children's difficulty in the mapping of unfamiliar pronunciations to known words in quiet listening conditions must rest on children's limited cognitive or linguistic skills and experiences. These results demonstrate that children's word recognition abilities under both environmental- and talker-related adversity are still developing in the early school-age years.

Children's perception of foreign-accented words

The acoustic-phonetic realizations of words can vary dramatically depending on a variety of within- and across-talker characteristics such as regional dialect, native language, age, and gender. Robust word learning requires that children are able to recognize words amidst this substantial variability. In the current study, perception of foreign-accented words was assessed in four- to seven-year-old children to test how one form of variability influences word recognition in children. Results demonstrated that children had less accurate word recognition than adults for both native- and foreign-accented words. Both adults and children were less accurate at identifying foreign-accented words compared to native-accented words with children and adults showing similar decrements. For children, age and lexicon size contributed to accurate word recognition.

Children's perception of dialect variation

A speaker's regional dialect is a rich source of information about that person. Two studies examined five- to six-year-old children's perception of regional dialect: Can they perceive differences among dialects? Have they made meaningful social connections to specific dialects? Experiment 1 asked children to categorize speakers into groups based on their accent; Experiment 2 asked them to match speakers to (un)familiar cultural items. Each child was tested with two of the following: the child's Home dialect, a Regional variant of that dialect, and a Second-Language variant. Results showed that children could successfully categorize only with a Home vs. Second-Language dialect contrast, but could reliably link cultural items with either a Home vs. Second-Language or a Regional vs. Second-Language dialect contrast. These results demonstrate five- to six-year-old children's developing perceptual skill with dialect, and suggest that they have a gradient representation of dialect variation.

Cross-accent intelligibility of speech in noise: long-term familiarity and short-term familiarization

Listeners must cope with a great deal of variability in the speech signal, and thus theories of speech perception must also account for variability, which comes from a number of sources, including variation between accents. It is well known that there is a processing cost when listening to speech in an accent other than one's own, but recent work has suggested that this cost is reduced when listening to a familiar accent widely represented in the media, and/or when short amounts of exposure to an accent are provided. Little is known, however, about how these factors (long-term familiarity and short-term familiarization with an accent) interact. The current study tested this interaction by playing listeners difficult-to-segment sentences in noise, before and after a familiarization period where the same sentences were heard in the clear, allowing us to manipulate short-term familiarization. Listeners were speakers of either Glasgow English or Standard Southern British English, and they listened to speech in either their own or the other accent, thereby allowing us to manipulate long-term familiarity. Results suggest that both long-term familiarity and short-term familiarization mitigate the perceptual processing costs of listening to an accent that is not one's own, but seem not to compensate for them entirely, even when the accent is widely heard in the media.

Linguistic processing of accented speech across the lifespan

In most of the world, people have regular exposure to multiple accents. Therefore, learning to quickly process accented speech is a prerequisite to successful communication. In this paper, we examine work on the perception of accented speech across the lifespan, from early infancy to late adulthood. Unfamiliar accents initially impair linguistic processing by infants, children, younger adults, and older adults, but listeners of all ages come to adapt to accented speech. Emergent research also goes beyond these perceptual abilities, by assessing links with production and the relative contributions of linguistic knowledge and general cognitive skills. We conclude by underlining points of convergence across ages, and the gaps left to face in future work.

Preschoolers' use of talker information in on-line comprehension

A crucial part of language development is learning how various social and contextual language-external factors constrain an utterance's meaning. This learning process is poorly understood. Five experiments addressed one hundred thirty-one 3- to 5-year-old children's use of one such socially relevant information source: talker characteristics. Participants learned 2 characters' favorite colors; then, those characters asked participants to select colored shapes, as eye movements were tracked. Results suggest that by preschool, children use voice characteristics predictively to constrain a talker's domain of reference, visually fixating the talker's preferred color shapes. Indicating flexibility, children used talker information when the talker made a request for herself but not when she made a request for the other character. Children's ease at using voice characteristics and possible developmental changes are discussed.

Accent processing in dementia

Accented speech conveys important nonverbal information about the speaker as well as presenting the brain with the problem of decoding a non-canonical auditory signal. The processing of non-native accents has seldom been studied in neurodegenerative disease and its brain basis remains poorly understood. Here we investigated the processing of non-native international and regional accents of English in cohorts of patients with Alzheimer's disease (AD; n=20) and progressive nonfluent aphasia (PNFA; n=6) in relation to healthy older control subjects (n=35). A novel battery was designed to assess accent comprehension and recognition and all subjects had a general neuropsychological assessment. Neuroanatomical associations of accent processing performance were assessed using voxel-based morphometry on MR brain images within the larger AD group. Compared with healthy controls, both the AD and PNFA groups showed deficits of non-native accent recognition and the PNFA group showed reduced comprehension of words spoken in international accents compared with a Southern English accent. At individual subject level deficits were observed more consistently in the PNFA group, and the disease groups showed different patterns of accent comprehension impairment (generally more marked for sentences in AD and for single words in PNFA). Within the AD group, grey matter associations of accent comprehension and recognition were identified in the anterior superior temporal lobe. The findings suggest that accent processing deficits may constitute signatures of neurodegenerative disease with potentially broader implications for understanding how these diseases affect vocal communication under challenging listening conditions.

Adaptation to novel accents by toddlers

Word recognition is a balancing act: listeners must be sensitive to phonetic detail to avoid confusing similar words, yet, at the same time, be flexible enough to adapt to phonetically variable pronunciations, such as those produced by speakers of different dialects or by non-native speakers. Recent work has demonstrated that young toddlers are sensitive to phonetic detail during word recognition; pronunciations that deviate from the typical phonological form lead to a disruption of processing. However, it is not known whether young word learners show the flexibility that is characteristic of adult word recognition. The present study explores whether toddlers can adapt to artificial accents in which there is a vowel category shift with respect to the native language. 18-20-month-olds heard mispronunciations of familiar words (e.g., vowels were shifted from [a] to [æ]: "dog" pronounced as "dag"). In test, toddlers were tolerant of mispronunciations if they had recently been exposed to the same vowel shift, but not if they had been exposed to standard pronunciations or other vowel shifts. The effects extended beyond particular items heard in exposure to words sharing the same vowels. These results indicate that, like adults, toddlers show flexibility in their interpretation of phonological detail. Moreover, they suggest that effects of top-down knowledge on the reinterpretation of phonological detail generalize across the phono-lexical system.

Phonological Knowledge in Typical and Atypical Speech-Sound Development

This article discusses 4 types of phonological knowledge: knowledge of the acoustic and perceptual characteristics of speech sounds (perceptual knowledge), knowledge of the articulatory characteristics of speech sounds (articulatory knowledge), higher level knowledge of the ways that words can be divided into sounds and related phonotactic constraints on how sounds can be combined into words (higher level phonological knowledge), and knowledge of the ways that variation in pronunciation can be used to convey social identity (social-indexical knowledge). The first section of the article discusses the nature of these types of knowledge in adults. The second describes how they develop in children with typical language development. The third section outlines how different types of knowledge may be compromised in children with functional speech-sound impairments. Together, these 3 sections serve as a review for practicing clinicians of the types of phonological knowledge that underlie accurate and fluent speech production.

Input that contradicts young children's strategy for mapping novel words affects their phonological and semantic interpretation of other novel words

Children tend to choose an entity they cannot already label, rather than one they can, as the likely referent of a novel noun. The effect of input that contradicts this strategy on the interpretation of other novel nouns was investigated. In pre- and posttests, 4-year-olds were asked to judge whether novel nouns referred to "name-similar" familiar objects or novel objects (e.g., whether japple referred to an apple or a binder clip). During an intervening treatment phase, they were asked to pick the referents of novel nouns from pairs of familiar objects (Experiments 1 and 3) or were taught subordinate names for familiar objects (Experiment 2). Most resisted the lure of phonological similarity in the pretest but increased selection of name-similar familiar objects over novel ones in the posttest. In Experiment 3, which involved monosyllables that differed in initial phoneme from the familiar words, treatment produced this effect only when accompanied by a rhyme-sensitization procedure. Experiment 2 included two other age groups: 2-year-olds, who were less resistant to phonological similarity in the pretest and responded to the treatment like the 4-year-olds; and adults, who nearly always selected the novel objects in the pretest and posttest. For children, the impact of treatment was positively associated with ability to detect phonological similarity and negatively associated with vocabulary size.