A longitudinal approach to phonetic enhancement in infant directed speech: normally hearing infants and hearing-impaired infants with a cochlear implant.

The aim of the present project is to investigate Infant Directed Speech (IDS). Since the pathbreaking work of i.a. Snow & Ferguson (1977) a consensus has grown that IDS exhibits particular characteristics that distinguish it from Adult Directed Speech (ADS). A case in point is the production of vowels: in IDS vowels are produced more "clearly" than in ADS, as can be inferred from the larger vowel space in IDS (Kuhl 2000). This "received wisdom" has recently been fundamentally questioned. For instance, Martin et al. (2015) conclude their study of Japanese IDS and ADS: "Mothers speak less clearly to infants than to adults." We want to further investigate this contradiction by replicating the findings reported in the literature using a large database of Dutch IDS and ADS, and by systematically scrutinizing two variables that have been largely neglected up till now: 1. longitudinal development: how does IDS change relative to chronological age and, more importantly, "linguistic age" as represented by a.o. the child's evolving cumulative vocabulary and utterance length? 2. characteristics of the child as interlocutor: does speech directed to a child with normal hearing (NH) differ from speech directed to a deaf child with a cochlear implant (CI)?

Keywords:COCHLEAR IMPLANTS, HEARING IMPAIRMENT

Disciplines:Linguistics, Theory and methodology of linguistics, Other languages and literary studies