Adult responses to infant prelinguistic vocalizations are associated with infant vocabulary: A home observation study.

Lukas D Lopez,Anne S Warlaumont,Eric A Walle,Gina M Pretzer,Iris Nomikou

doi:10.1371/journal.pone.0242232

Lukas D Lopez, Anne S Warlaumont + Show 3 more

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https://doi.org/10.1371/journal.pone.0242232

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Abstract

This study used LENA recording devices to capture infants' home language environments and examine how qualitative differences in adult responding to infant vocalizations related to infant vocabulary. Infant-directed speech and infant vocalizations were coded in samples taken from daylong home audio recordings of 13-month-old infants. Infant speech-related vocalizations were identified and coded as either canonical or non-canonical. Infant-directed adult speech was identified and classified into different pragmatic types. Multiple regressions examined the relation between adult responsiveness, imitating, recasting, and expanding and infant canonical and non-canonical vocalizations with caregiver-reported infant receptive and productive vocabulary. An interaction between adult like-sound responding (i.e., the total number of imitations, recasts, and expansions) and infant canonical vocalizations indicated that infants who produced more canonical vocalizations and received more adult like-sound responses had higher productive vocabularies. When sequences were analyzed, infant canonical vocalizations that preceded and followed adult recasts and expansions were positively associated with infant productive vocabulary. These findings provide insights into how infant-adult vocal exchanges are related to early vocabulary development.

Highlights

Language learning occurs in an inherently social context co-constructed by the infant and their caregivers
While research indicates that the total amount of infant directed speech (IDS) heard in the home is a determinate of language outcomes [3,4], it has been shown that high-quality in home one-on-one interactions containing IDS are associated with infant vocabulary development over and above the total amount of IDS heard [5,6]
The proportion of babbling that was canonical (.27) compared to that which was noncanonical (.73) babbling was comparable to canonical babbling ratios (CBR) reported at the syllable level in previous lab research with same aged infants (CBR = .27 to .30; [49]; CBR = .34; [41]), and, not surprisingly, higher than canonical babbling ratios reported for 11-month old infants in similar naturalistic observations (CBR = .11; [29])

Summary

Introduction

Language learning occurs in an inherently social context co-constructed by the infant and their caregivers. While research indicates that the total amount of infant directed speech (IDS) heard in the home is a determinate of language outcomes [3,4], it has been shown that high-quality in home one-on-one interactions containing IDS are associated with infant vocabulary development over and above the total amount of IDS heard [5,6]. Such dyadic contexts may propagate contingent infant-caregiver vocal turn-taking containing infant speech-.

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