Language Production, Incremental Processing in

Generating Grammatical Structure

There is conflicting evidence about how much of an utterance must be grammatically encoded prior to articulation. Some theories claim that the verb of a sentence must be retrieved before the generation of syntactic structure can commence. Verbs control the structure of clauses and there is evidence that the clause operates as a planning unit during speech production. Planning pauses in speech have been shown to occur more frequently between clauses than clause internally. Speech error data have been used to claim that the words for a whole clause are retrieved prior to speech onset. Word exchange errors such as “put the drawer in the cloth” suggest that the exchanging words drawer and cloth are retrieved in parallel. However, it is also proposed that these effects could occur during conceptual, rather than grammatical, processing.

Experimental evidence exists for tightly incremental planning. In recent years, eye-tracking studies have recorded the gaze patterns of speakers while they describe pictured scenes. These experiments demonstrate that speakers almost always fixate on pictured objects in their order of mention and rarely look ahead at objects to be named later (although some peripheral processing of immediately adjacent objects can occur). The time spent looking at an object is a function of the ease with which it can be identified, as well as of the ease with which the phonological form of its name can be retrieved. These findings suggest that we plan speech word-byword with planning progressing only slightly ahead [Page 464]of articulation. However, these experiments usually involved the production of one sentence structure to one fixed pattern of pictures. It is possible, therefore, that the observed visual and linguistic processing patterns are strategic rather than typical.

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