Tailoring the Input to Children's Needs: The Use of Fine Lexical Tuning in Speech Directed to Normally Hearing Children and Children With Cochlear Implants.

Lotte Odijk,Steven Gillis

doi:10.3389/fpsyg.2021.676664

Abstract

Purpose: The aim of the present study was to explore fine lexical tuning in Dutch infant-directed speech (IDS) addressed to congenitally deaf infants who received a cochlear implant (CI) early in life (<2 years of age) in comparison with children with normal hearing (NH). The longitudinal pattern of parents' utterance length in the initial stages of the child's lexical development was examined. Parents' utterances containing the words the children eventually acquired in the earliest developmental stages were selected and their MLU (Mean Length of Utterance) was measured.Method: Transcriptions of monthly recordings of spontaneous interactions of 10 CI children and 30 NH children with their parents were analyzed. The children with CI were followed from the moment their device was switched on, and the NH children from the age of 6 months onwards. A total of 57,846 utterances of parents of CI children and 149,468 utterances of parents of NH children were analyzed.Results: IDS addressed to children with NH and children with CI exhibits fine lexical tuning: parents adjust the MLU of the utterances that contain the words that children are on the verge of producing themselves. More specifically, the parents' mean length of those utterances decreased in relation to the point when the children began using the item. Consequently, the number of occurrences in isolation of the lexical item increased. The speech addressed to all the children exhibited this phenomenon, but it was significantly more strongly present in speech addressed to the children with CI.Conclusions: The speech addressed to children with NH and CI is characterized by fine lexical tuning and a high incidence of single-word utterances in the period leading up to the children's first use of words in speech production. Notwithstanding striking commonalities, IDS addressed to children with a hearing impairment is markedly different, which suggests that parents take this specific character of the children into account.

Highlights

Infant Directed Speech (IDS) is a simplified register that adults often use with their infants
Coarse tuning was analyzed in IDS addressed to children with different hearing characteristics, congenitally deaf children with a cochlear implant and children with normal hearing
With respect to fine lexical tuning: did parents adjust their speech at the level of individual words? And did they shorten their utterances containing the words in the period leading up to the words’ first appearance in the child’s speech, the so-called “word birth?”

Summary

Introduction

Infant Directed Speech (IDS) is a simplified register that adults often use with their infants. The register is characterized by specific adaptations as compared to Adult Directed Speech (ADS), such as shorter and simplified utterances, a higher pitch, a greater variability in pitch, a larger vowel space and a slower speaking rate (Phillips, 1973; Snow, 1977; Fernald et al, 1989; Soderstrom, 2007; Ko, 2012; Cristia, 2013; Wieland et al, 2015). IDS supports word learning in the early stages of lexical acquisition. 27-month-olds learned novel words presented in both IDS and ADS, implying that IDS has a larger influence on word learning in the early stages of lexical development (Ma et al, 2011). IDS appears to be important for lexical acquisition, especially in the earlier stages of lexical development

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