Normal and impaired processing in quasi-regular domains of language: the case of English past-tense verbs

Karalyn Patterson, Matthew A. Lambon Ralph, Helen Bird, John R. Hodges, James L. McClelland

Abstract: In most if not all languages, there are domains in which the relationship between one form of a word and another can be described as quasi-regular [1]. This means that, across the whole relevant vocabulary, there is substantial but imperfect consistency in the nature of the transformation linking the two forms. Quasi-regularity may apply between the same word forms in different modalities, as in the spoken and written versions of words, and also between different morphological forms of the same word root. In many languages, some aspects of verb morphology have this feature. The majority of English verbs, for example, are transformed to past tense by simply adding -ed to the present tense form (e.g., talk -> talked). The remainder, which include some of the most commonly used verbs in the language, form their past tenses in an atypical way (e.g., speak -> spoke; think -> thought; have -> had).