How an aglossic speaker produces an alveolar-like percept without a functional tongue tip

Abstract

It has been previously observed [McMicken, Salles, Berg, Vento-Wilson, Rogers, Toutios, and Narayanan. (2017). J. Commun. Disorders, Deaf Stud. Hear. Aids 5(2), 1–6] using real-time magnetic resonance imaging that a speaker with severe congenital tongue hypoplasia (aglossia) had developed a compensatory articulatory strategy where she, in the absence of a functional tongue tip, produced a plosive consonant perceptually similar to /d/ using a bilabial constriction. The present paper provides an updated account of this strategy. It is suggested that the previously observed compensatory bilabial closing that occurs during this speaker's /d/ production is consistent with vocal tract shaping resulting from hyoid raising created with mylohyoid action, which may also be involved in typical /d/ production. Simulating this strategy in a dynamic articulatory synthesis experiment leads to the generation of /d/-like formant transitions.