Two experiments are reported, eliciting segmental speech errors and self- repairs. Error frequencies, detection frequencies, error-to-cutoff times and cutoff-to-repair times were assessed with and without auditory feedback, for errors against four types of segmental oppositions. Main hypotheses are (a) prearticulatory and postarticulatory detection of errors is reflected in a bimodal distribution of error-to-cutoff times; (b) after postarticulatory error detection repairs need to be planned in a time-consuming way, but not after prearticulatory detection; (c) postarticulatory error detection depends on auditory feedback.

Results confirm hypotheses (a) and (b) but not (c). Internal and external detection are temporally separated by some 500 ms on average, fast and slow repairs by some 700 ms. Error detection does not depend on audition. This seems self-evident for prearticulatory but not for postarticulatory error detection. Theoretical implications of these findings are discussed.