Articulatory compensation strategies employed by an aglossic speaker
Asterios Toutios, Dani Byrd, Louis Goldstein, Shrikanth Shri Narayanan · The Journal of the Acoustical Society of America · 2017
We are employing real-time MRI to probe the speech production patterns of a speaker with congenital aglossia, a rare syndrome in which an individual is born without a tongue. The speaker being studied has only a small stump-like tongue rudiment in the region of the tongue root and a hypertrophied floor of the mouth (mylohyoid) and base of the tongue. Nevertheless, the speaker has acquired the ability to produce highly intelligible speech. One initial finding is that the speaker, in the absence of a tongue tip, produces plosive consonants that are perceptually similar to /t/ and /d/ by using a bilabial constriction with a significantly increased anteroposterior extent (relative to her /p/ or /b/ productions). Our aim is to provide an articulatory-acoustic account of this compensatory strategy via detailed analysis of her production strategies as evidenced in the real-time MRI data and via simulations using an articulatory synthesizer. We examine whether the increased anteroposterior extent of the bilabial constriction can by itself fully explain its coronal-like percept, or whether other factors contribute, such as the overall shaping of the back cavity or the dynamics of the “laminal” bilabial (pseudo-coronal) constriction formation and release. [Work supported by NIH.]