A re-evaluation of the nature of speech errors in normal and disordered speakers.

It is well known that speech errors in normal and aphasic speakers share certain key characteristics. Traditionally, many of these errors are regarded as serial misorderings of abstract phonological segments, which maintain the phonetic well-formedness of the utterance. The current paper brings together the results of several articulatory studies undertaken independently for both subject populations. These show that, in an error, instead of one segment substituting for another, two segments are often produced simultaneously even though only one segment may be heard. Such data pose problems for current models of speech production by suggesting that the commonly assumed dichotomous distinction between phonological and phonetic errors may not be tenable in the current form or may even be altogether redundant.