Part-word repetitions by persons who stutter: fragment types and their articulatory processes

One of the core features of developmental stuttering is part-word repetition followed by fluent production (resolution) of the target word. The purpose of the study is to compare the spectro-temporal dimensions of fragments with the spectro-temporal dimensions of the resolution to define fragment types and develop articulatory interpretation of termination-restart cycles. From the acoustic recordings of six adult males who stutter, 142 stuttering events on words beginning with stops were isolated, excerpted, and digitized. The stuttering events occurred during either spontaneous speech or reading. The consecutive articulatory phases of fragments were classified and compared with the corresponding phases in resolutions. We found that (a) there are two basic types of fragments--those with vowels and those without, (b) the type of fragment produced is strongly influenced by the voicing status of the stop, (c) the fragments without vowels tend to have longer stop closure duration than the stops in the resolutions, (d) there are two subtypes in fragments with vowels--those with vowels shorter than and those with vowels longer than the vowels in the resolutions, (e) the shorter vowels differ spectro-temporally from the vowels in resolutions, and (f) the longer vowels differ temporally from the vowels in the resolutions. We discuss the articulatory implications of the acoustic data for each fragment type in the context of speech as an act designed to achieve contextually conditioned acoustic goals.