Form-oriented inflectional errors in language processing

We examine speech errors as a way of understanding fundamental aspects of cognitive processing. Our studies focus on one type of speech error: the failure to add an inflection to a word because the adjacent part of the base word is identical to the inflection. Errors of this type reflect a more general problem with the repetition of actions in cognitive processing. Such errors indicate that language processing is sensitive to the form of the output even as it is generating that output. We demonstrate that form-oriented errors occur in production tasks for past tense -ed, present tense -s, indefinite a/an, and three irregular past tense patterns. The data support the following strong principle in language production: if a form resembles the output of an inflectional pattern, there will be a tendency to use it without actually applying that pattern. We also show that when the base word resembles an irregular pattern, the members of the irregular pattern function as a “gang” to impose their shape on the base word, but this does not appear to be the case when the base word resembles a regular pattern. Implications of these effects for models of language and cognitive processing are discussed.