SPEECH: UNIT OF PRODUCTION
A number of phonological units of analysis can be identified in connected speech. They include the phonetic feature (voicing, nasality etc.); the phoneme; the syllable; the rhythmic foot; the phonological phrase; the intonational phrase. It is difficult to determine which plays a primary role in the assembly of speech. The units cited are perceptual ones, which may not have the same relevance for a speaker as they do for a listener.
Empirical evidence for a unit of speech planning has been sought in pausing, in speech errors, in intonation patterns and in the gestures which accompany speech. There are conflicting findings; and a reasonable conclusion seems to be that different units are available at different levels of processing.
Pauses for planning have been shown to occur consistently at the ends of syntactic clauses, suggesting that the clause plays an important part. But even here the situation is not entirely clear. The boundary of a syntactic clause is often also the boundary of a phonological phrase or an intonational phrase. And the reasons for employing a unit of this size may be semantic rather than syntactic, deriving from the formation of a predicate/argument structure.
At the final, phonetic, stage of planning, the phoneme is an unlikely unit of analysis because it varies so much according to the context in which it occurs. Some commentators suggest that articulatory information is stored in the form of syllable-level operations. Further evidence for the importance of the syllable comes from Slip of the Tongue data, which shows that syllable structure is very robust. A sound that occurs at the beginning of a syllable is rarely transposed with one that occurs at the end.
See also: Unit of perception
