Phonological priming effects in stutterers

It is hypothesized that stuttering is caused by a perturbation of phonological encoding, i.e., the construction of the fully specified articulatory program on the basis of word form information stored in the mental lexicon. Nine stutterers and nine nonstutterers participated in a phonological priming experiment. In each trial, they were required to utter one word from a set of five as fast as possible upon visual presentation of a related cue word. In the so-called homogeneous conditions, the response words shared initial segments, either the initial consonant or the initial consonant and the subsequent vowel. In the heterogeneous conditions, the response words were phonemically unrelated. Nonstutterers had shorter speech onset latencies in the homogeneous conditions than in the heterogeneous conditions, and the difference was larger for the words sharing both consonant and vowel than for the words sharing the initial consonant only. In most stutterers, a reduction of speech onset occurred only when the words shared both consonant and vowel. These results are taken to indicate that in stutterers the encoding of noninitial parts of syllables, particularly the (stressed) vowel, is delayed. The primary symptoms of stuttering-repetition or prolongation of syllable-initial segments-are argued to result from attempts at executing a syllable prior to the incorporation of correct vowel information in the articulatory plan.