Articulation Without Oral Sensory Control

Oral sensory deprivation was induced in two subjects by nerve block injections, and the effect on articulation was investigated. Twenty-four bisyllabic words produced under control and nerve block conditions were phonetically transcribed according to a close transcription scheme. Wide-band spectrograms provided acoustic information which was helpful in clarifying certain articulatory events. Articulatory changes caused by deprivation were largely nonphonemic in nature and included the loss of retroflexion and liprounding gestures, less close fricative constrictions, and retracted place of articulation. Results were interpreted to suggest that speech control involves a closed-loop component which is operative for certain types of articulatory events and not for others.