Vocalic activation width decreases across childhood: Evidence from carryover coarticulation

Aude Noiray,Elina Rubertus

doi:10.5334/labphon.228

Abstract

This study is the first to use kinematic data to assess lingual carryover coarticulation in children. We investigated whether the developmental decrease previously attested in anticipatory coarticulation, as well as the relation between coarticulatory degree and the consonantal context, also characterize carryover coarticulation. Sixty-two children and 13 adults, all native speakers of German, were recruited according to five age cohorts: three-year-olds, four-year-olds, five-year-olds, seven-year-olds, and adults. Tongue movements during the production of ə.CV.Cə utterances (C = /b, d, g/, V = /i, y, e, a, o, u/) were recorded with ultrasound. We measured vowel-induced horizontal displacement of the tongue dorsum within the last syllable and compared the resulting coarticulatory patterns between age cohorts and consonantal contexts. Results indicate that the degree of vocalic carryover coarticulation decreases with age. Vocalic prominence within an utterance as well as its change across childhood depended on the postvocalic consonant’s articulatory demands for the tongue dorsum (i.e., its coarticulatory resistance): Low resistant /b/ and /g/ allowed for more vocalic perseveration and a continuous decrease, while the highly resistant /d/ displayed lower coarticulation degrees and discontinuous effects. These findings parallel those in anticipation suggesting a similar organization of anticipatory and carryover coarticulation. Implications for theories of speech production are discussed.

Highlights

The investigation of coarticulatory effects, that is, the overlap of articulatory units in spoken language, served as a window to speech planning and execution mechanisms in adults over the last 60 years
For each age cohort and consonant context, the pattern of carryover coarticulation is described according to three parameters: the dependent variable horizontal tongue dorsum position in the course of the utterance, and the two independent variables time point and
Utterances containing the alveolar stop /d/ displayed a pattern differing tremendously from that of /b/ and /g/ contexts, we found evidence for a developmental decrease of vocalic activation here as well: While during the domain of the consonant the vocalic impact was lower in children than in adults, children produced the final schwa with tongue dorsum positions resembling more those of the vowel than adults’

Summary

Introduction

The investigation of coarticulatory effects, that is, the overlap of articulatory units in spoken language, served as a window to speech planning and execution mechanisms in adults over the last 60 years (for a review see Recasens, 2018). The present study focuses on the development of lingual carryover coarticulation across childhood, the overlap of a speech segment with following ones after its target was reached. While anticipatory coarticulation has often been described as a sign of speech planning, carryover coarticulation was ascribed to mechanical inertia constraints (e.g., Recasens, 1984b) and was largely understudied. We suggest that both anticipatory and carryover coarticulation are the consequence of the overlap of gestural activation. The parallelism of the development of carryover coarticulation as found in the present study and anticipatory coarticulation as previously reported, provides evidence for this hypothesis

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