Some properties of mental speech preparation as revealed by self-monitoring

The main goal of this paper is to improve our insight in the mental preparation of speech, based on speakers' self-monitoring behavior. To this end we re-analyze the aggregated responses from earlier published experiments eliciting speech sound errors. The re-analyses confirm or show that (1) “early” and “late” detections of elicited speech sound errors can be distinguished, with a time delay in the order of 500 ms; (2) a main cause for some errors to be detected “early”, others “late” and others again not at all is the size of the phonetic contrast between the error and the target speech sound; (3) repairs of speech sound errors stem from competing (and sometimes active) word candidates. These findings lead to some speculative conclusions regarding the mental preparation of speech. First, there are two successive stages of mental preparation, an “early” and a “late” stage. Second, at the “early” stage of speech preparation, speech sounds are represented as targets in auditory perceptual space, at the “late” stage as coordinated motor commands necessary for articulation. Third, repairs of speech sound errors stem from response candidates competing for the same slot with the error form, and some activation often is sustained until after articulation.