Input quality and speech perception development in bilingual infants' first year of life

Epub 2021 Oct 20Individual differences in infants’ native phonological development have been linked to the quantity and quality of infant-directed speech (IDS). The effects of parental and infant bilingualism on this relation in 131 five-and nine-month- old monolingual and bilingual Spanish and Basque infants (72 male; 59 female; from white middle-class background) were investigated. Bilingualism did not affect the developmental trajectory of infants’ native and non-native speech perception and the quality of maternal speech. In both language groups, vowel exaggeration in IDS was significantly related to speech perception skills for 9-month- olds (r = −.30), but not for 5-month- olds. This demonstrates that bilingual and monolingual caregivers provide their infants with speech input that assists their task of learning the phonological inventory of one or two languages.Eusko Jaurlaritza, Grant/Award Number: BERC 2018-2021; Severo Ochoa Excellence Program, Grant/Award Number: SEV-2015- 0490; Ministerio de Ciencia e Innovación, Grant/Award Number: PID2019-105528GA- I00; H2020 Marie Skłodowska-Curie Actions, Grant/Award Number: 79890

Mutual exclusivity develops as a consequence of abstract rather than particular vocabulary knowledge

Mutual exclusivity (ME) refers to the assumption that there are one-to-one relations between linguistic forms and their meanings. It is used as a word-learning strategy whereby children tend to map novel labels to unfamiliar rather than familiar referents. Previous research has indicated a relation between ME and vocabulary development, which could either be due to children's developing knowledge of the labels for familiar objects, or to enhanced general word-learning skills. In this study, ME was related to receptive vocabulary for 17- to 19-month-old children in a novel paradigm where children's familiarity with the objects and labels was controlled. It was found that infants with larger receptive vocabularies employed ME to a greater extent than infants with a smaller vocabulary size. The results indicate that ME use is more reliable in infants with larger receptive vocabulary size, and, critically, that ME gradually consolidates as an abstract word-learning strategy as infants' linguistic experience increases

Infants’ Sensitivity to Lexical Tone and Word Stress in Their First Year: A Thai and English Cross- Language Study

Published online: 23 Aug 2021Non-tone language infants’ native language recognition is based first on supra-segmental then segmental cues, but this trajectory is unknown for tone-language infants. This study investigated non-tone (English) and tone (Thai) language 6- to 10-month-old infants’ preference for English vs. Thai one-syllable words (containing segmental and tone cues) and two-syllable words (additionally containing stress cues). A preference for their native onesyllable words was observed in each of the two groups of infants, but this was not the case for two-syllable words where Thai-learning infants showed no native-language preference. These findings indicate that as early as six months of age, infants acquiring tone- and non-tone languages identify their native language by relying solely on lexical tone cues, but tone language infants no longer show successful identification of their native language when two pitch-based cues co-occur in the signal.The first author’s work was supported by the European Union’s Horizon 2020 Marie Sklodowska-Curie individual Fellowships European Programme under Grant Agreement No 798908 Optimising IDS, and she receives support from the Basque Government through the BERC 2018–2021 program, and from the Spanish Ministry of Science and Innovation through the Ramon y Cajal Research Fellowship, PID2019–105528GA-I00

Acoustic features of infant-directed speech to infants with hearing loss

Published Online: 03 December 2020This study investigated the effects of hearing loss and hearing experience on the acoustic features of infant-directed speech (IDS) to infants with hearing loss (HL) compared to controls with normal hearing (NH) matched by either chronological or hearing age (experiment 1) and across development in infants with hearing loss as well as the relation between IDS features and infants' developing lexical abilities (experiment 2). Both experiments included detailed acoustic analyses of mothers' productions of the three corner vowels /a, i, u/ and utterance-level pitch in IDS and in adult-directed speech. Experiment 1 demonstrated that IDS to infants with HL was acoustically more variable than IDS to hearing-age matched infants with NH. Experiment 2 yielded no changes in IDS features over development; however, the results did show a positive relationship between formant distances in mothers' speech and infants' concurrent receptive vocabulary size, as well as between vowel hyperarticulation and infants' expressive vocabulary. These findings suggest that despite infants' HL and thus diminished access to speech input, infants with HL are exposed to IDS with generally similar acoustic qualities as are infants with NH. However, some differences persist, indicating that infants with HL might receive less intelligible speech.This research was supported by HEARing Cooperative Research Centre Grant No. 82631, “The Seeds of Language Development,” to D.B. The second author's work is supported by the Basque Government through the BERC 2018-2021 program and by the Spanish Ministry of Science and Innovation through the Ramon y Cajal Research Fellowship PID2019-105528GA-I00. We would like to thank all the parents and infants for participating in the study; “The Shepherd Centre” in Sydney and Wollongong; “Hear and Say” in Brisbane for their help in recruitment of participants with HL; and Benjawan Kasisopa, Maria Christou-Ergos, Hana Zjakic, and Scott O'Loughlin for their assistance with data collection

The effects of bilingualism on attentional processes in the first year of life

First published: 30 June 2020Bilingualism is a powerful experiential factor, and its effects have been proposed to extend beyond the linguistic domain by boosting the development of executive functioning skills. Crucially, recent findings suggest that this effect can be detected in bilingual infants before their first birthday indicating that it emerges as a result of early bilingual exposure and the experience of negotiating two linguistic systems in infants' environment. However, these conclusions are based on only two research studies from the last decade (Comishen, Bialystok, & Adler, 2019; Kovács & Mehler, 2009), so to date, there is a lack of evidence regarding their replicability and generalizability. In addition, previous research does not shed light on the precise aspects of bilingual experience and the extent of bilingual exposure underlying the emergence of this early bilingual advantage. The present study addressed these two questions by assessing attentional control abilities in 7-month-old bilingual infants in comparison to same-age monolinguals and in relation to their individual bilingual exposure patterns. Findings did not reveal significant differences between monolingual and bilingual infants in the measure of attentional control and no relation between individual performance and degree of bilingual exposure. Bilinguals showed different patterns of allocating attention to the visual rewards in this task compared to monolinguals. Thus, this study indicates that bilingualism modulates attentional processes early on, possibly as a result of bilinguals' experience of encoding dual-language information from a complex linguistic input, but it does not lead to significant advantages in attentional control in the first year of life.Eusko Jaurlaritza, Grant/Award Number: BERC 2018-2021; Spanish State Research Agency Severo Ochoa Excellence Accreditation, Grant/Award Number: SEV- 2015-0490; H2020 Marie Skłodowska-Curie Actions, Grant/Award Number: 79890

Delayed development of phonological constancy in toddlers at family risk for dyslexia

Available online 20 June 2019.Phonological constancy refers to infants’ ability to disregard variations in the phonetic realisation of speech sounds that do not indicate lexical contrast, e.g., when listening to accented speech. In typically-developing infants, this ability develops between 15- and 19-months of age, coinciding with the consolidation of infants’ native phonological competence and vocabulary growth. Here we investigated the developmental time course of phonological constancy in infants at family risk for developmental dyslexia, using a longitudinal design. Developmental dyslexia is a disorder affecting the acquisition of reading and spelling skills, and it also affects early auditory processing, speech perception, and lexical acquisition. Infants at-risk and not at-risk for dyslexia, based on a family history of dyslexia, participated when they were 15-, 19-, and 26-months of age. Phonological constancy was indexed by comparing at-risk and not at-risk infants’ ability to recognise familiar words in two preferential looking tasks: (1) a task using words presented in their native accent, and (2) a task using words presented in a non-native accent. We expected a delay in phonological constancy for the at-risk infants. As predicted, in the non-native accent task, not at-risk infants recognised familiar words by 19 months, but at-risk infants did not. The control infants thus exhibited phonological constancy. By 26 months, at-risk toddlers did show successful word recognition in the native accent task. However, for the non-native accent task at 26 months, neither at-risk nor control infants showed familiar word recognition. These findings are discussed in terms of the impact of family risk for dyslexia on toddlers’ consolidation of early phonological and lexical skills.This research was supported by the Australian Research Council grant DP110105123, ‘The Seeds of Literacy’, to the 3rd and 2nd authors

The Role of Paired Associate Learning in Acquiring Letter-Sound Correspondences: A Longitudinal Study of Children at Family Risk for Dyslexia

Published online: 08 Dec 2020Visual-verbal-paired associate learning (PAL) is strongly related to reading acquisition, possibly indexing a distinct cross-modal mechanism for learning letter-sound associations. We measured linguistic abilities (nonword repetition, vocabulary size) longitudinally at 3.5 and 4.0 years, and visual-verbal PAL and letter knowledge at 4.0 and 4.5 years, in pre-reading children either at family risk for dyslexia (N = 27) or not (N = 25). Only nonword repetition predicted individual differences in later letter-sound knowledge, and PAL did not make a cross-sectional nor a longitudinal contribution. The data show a continuous relationship between linguistic processing abilities and letter-sound learning, with no independent role for PAL.This research was supported by the Australian Research Council grant DP110105123, ‘The Seeds of Literacy’, to the 2nd and 3rd authors. The first author’s work is supported by the Basque Government through the BERC 2018-2021 program and by the Spanish Ministry of Science and Innovation through the Ramon y Cajal Research Fellowship, PID2019-105528GA-I00

Acceptance of lexical overlap by monolingual and bilingual toddlers

Article first published online: October 31, 2018Aims and Objectives: Mutual exclusivity refers to children’s assumption that there are oneto-one correspondences between words and their referents. It is proposed to guide the process of fast-mapping when children encounter novel words in referentially ambiguous situations. However, children are often required to suspend this default assumption and accept lexically overlapping labels, which is particularly common for bilingual children who learn multiple labels for most referents in their environment. Previous research has shown that school-aged bilinguals are more successful at learning overlapping labels than monolinguals, but the mechanisms underlying the development of this word-learning ability remain unknown. Methodology: This study investigated the ability to accept lexical overlap in monolingual and bilingual two-and-a-half-year-old children and its relation to children’s lexical competence. Children’s ability to retain two novel labels assigned to a novel referent was assessed in an interactive lexical overlap paradigm. In addition, parental inventories were used to measure children’s receptive vocabulary size and patterns of language exposure and use. Data and analysis: Data were collected from 68 (34 monolingual and 34 bilingual) children between 26 and 34 months of age. Binomial logistic regressions were used to assess the effects of children’s language background and their individual lexical competence (receptive vocabulary for monolinguals and bilinguals, and conceptual vocabulary size and degree of bilingualism for bilinguals). Findings: Results showed that vocabulary size was a significant predictor of lexical overlap performance for monolingual children, but this was not the case for bilinguals.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by Western Sydney University Researcher Development Funding (Women’s Research Fellowship) on behalf of the first author

Integrating Bilingualism, Verbal Fluency, and Executive Functioning across the Lifespan

Published online: 29 Aug 2019Bilingual experience has an impact on an individual’s linguistic processing and general cognitive abilities. The relation between these linguistic and non-linguistic domains, in turn, is mediated by individual linguistic proficiency and developmental changes that take place across the lifespan. This study evaluated this relationship by assessing inhibition skills, and verbal fluency in monolingual and bilingual school-aged children (Experiment 1), young adults (Experiment 2), and older adults (Experiment 3). Results showed that bilinguals outperformed monolinguals in the measure of inhibition, but only in the children and older adult age groups. With regards to verbal fluency, bilingual children outperformed their monolingual peers in the letter verbal fluency task, but no group differences were observed for the young and old adults. These findings suggest that bilingual experience leads to significant advantages in linguistic and non-linguistic domains, but only at the time points when these skills undergo developmental changes.This work was supported by the Australian Research Council [DE150101053]

The Acoustic Features and Didactic Function of Foreigner-Directed Speech: A Scoping Review

Published online: Aug 1, 2022Purpose: This scoping review considers the acoustic features of a clear speech register directed to nonnative listeners known as foreigner-directed speech (FDS). We identify vowel hyperarticulation and low speech rate as the most representative acoustic features of FDS; other features, including wide pitch range and high intensity, are still under debate. We also discuss factors that may influence the outcomes and characteristics of FDS. We start by examining accommodation theories, outlining the reasons why FDS is likely to serve a didactic function by helping listeners acquire a second language (L2). We examine how this speech register adapts to listeners’ identities and linguistic needs, suggesting that FDS also takes listeners’ L2 proficiency into account. To confirm the didactic function of FDS, we compare it to other clear speech registers, specifically infant-directed speech and Lombard speech. Conclusions: Our review reveals that research has not yet established whether FDS succeeds as a didactic tool that supports L2 acquisition. Moreover, a complex set of factors determines specific realizations of FDS, which need further exploration. We conclude by summarizing open questions and indicating directions and recommendations for future research.This research was supported by a Doctoral Fellowship (LCF/BQ/DI19/11730045) from “La Caixa” Foundation (ID 100010434) awarded to Giorgio Piazza and by the Spanish Ministry of Science and Innovation through the Ramon y Cajal Research Fellowship (RYC2018-024284-I) awarded to Marina Kalashnikova. This research was supported by the Basque Government through the BERC 2022-2025 program and by the Spanish State Research Agency through BCBL Severo Ochoa excellence accreditation CEX2020-001010-S. This research was also supported by the Spanish Ministry of Economy and Competitiveness (PID2020-113926GB-I00 awarded to Clara D. Martin) and by the European Research Council under the European Union’s Horizon 2020 research and innovation programme (Grant Agreement 819093 awarded to Clara D. Martin)