Markedness analysis of phonemic substitution errors in apraxia of speech.

The phonemic substitution errors of ten apractic speakers were analyzed to investigate the effects of markedness on speech production patterns. Results revealed that: more errors were produced on phonemes high in markedness; more changes in markedness were from marked to unmarked than unmarked to marked; and errors and directional changes in markedness were positively correlated with ease of articulation. The findings were interpreted as a systematic effort by the apractic speakers to reduce the complexity of articulatory gestures required to produce phonemes.