The effect of selected prosodic errors on the intelligibility of deaf speech

A trained speech pathologist listened to recordings of 40 deaf children, each reading 15 sentences and recorded instances of four types of prosodic errors: adventitious sounds, excessive phoneme duration, pitch breaks, and pauses. The scores were correlated with previously obtained intelligibility scores. It was found that adventitious sounds, except those obviously operating as transitional sounds to ease the movement from one place of articulation to another, had the greatest negative effect on intelligibility, followed by very long duration and pitch breaks. Medium and long pauses, long duration, prologned closure (i.e., long duration plosives), and adventitious transitional sounds had a lesser negative effect. Short pauses had a small positive effect on intelligibility. The method used to identify the errors was one that can hopefully be evolved into an evaluative instrument for practical use in schools for the deaf.