Marking word boundaries to improve the intelligibility of the speech of the deaf.

Speech of deaf talkers has often been characterized as staccato, leading to the perception of improper grouping of syllables. In an attempt to compensate for this syllabication, word boundaries of 30 sentences spoken by 10 deaf children were acoustically marked by means of silent pauses with a duration of 160 ms inserted between words. Subsequent tests with normal-hearing listeners demonstrated that after insertion of pauses the intelligibility of the sentences increased significantly (p less than .01) from 27% to 31%. A control measure showed that this increase was not merely due to a general deceleration of speech rate: When all phonemes were lengthened until the same sentence duration was obtained as after insertion of pauses, a (nonsignificant) decrease in intelligibility (M = 26%) resulted. The results are compared to earlier studies of speech of the deaf in which segmental and suprasegmental aspects were manipulated.