Back from the future: Nonlinear anticipation in adults and children's speech

Purpose: This study examines the temporal organization of vocalic anticipation in German children from 3 to 7 years of age and adults. The main objective was to test for non-linearprocesses in vocalic anticipation, which may result from the interaction between lingualgestural goalsfor individual vowels, and those for their neighbors over time. Method: The technique of ultrasound imaging was employed to record tongue movement at fivetimepoints throughout short utterances of the form V1#CV2. Vocalic anticipation was examined with Generalized Additive Modeling, an analytical approach allowing forthe estimation of both linear and non-linearinfluences on anticipatoryprocesses. Results: both adults and children exhibit non-linear patterns of vocalic anticipation over time with the degree and extent of vocalic anticipation varying as a function of the individual consonants and vowels assembled. However, noticeable developmental discrepancieswere found with vocalic anticipation being present earlier in children ́sutterances at 3-4-5 years of agein comparison to adults and to some extent 7-year-old children.Conclusions: Anarrowing of speech production organization from large chunks in kindergarten to more contextually-specified organizationsseems to occur fromkindergarten toprimary school toadulthood, although variation in the temporal overlap of lingual gestures for consecutive segments is already present in the youngestcohorts. In adults, non-linear anticipatory patterns over time suggest a strong differentiation between the gestural goals for consecutive segments. In children, this differentiation is not yet mature: vowelsshow greater prominence over time and seem activated more in-phase with those of previous segments relative to adults.