Brain responses to morphologically complex verbs: An electrophysiological study of Swedish regular and irregular past tense forms.

The present electrophysiological study investigated irregular versus regular verb form processing in Swedish during reading. In line with previous results from other languages, overregularized verbs, i.e. incorrect irregular stem + regular past tense suffix combinations (e.g. * stjäl + de 'steal + past tense'), elicited a left-lateralized negativity (LAN) relative to correct irregulars (stal 'stole'), suggesting rule-based decomposition of regularly inflected words. Lack of a similar effect for misapplication of the irregular stem formation pattern on regular verbs (e.g. * löft 'lifted' instead of lyfte) suggests the involvement of different processing mechanisms, possibly whole word access, for irregular items, at least to some degree. A P600 showing reprocessing was seen for all incorrect forms. The results add cross-linguistic support for morphological decomposition in the verbal inflection of a language where results from previous neurolinguistic studies of nominal inflection have only suggested the use of full-form access to words. • ERPs of both overregularized and irregularized verbs in Swedish were recorded. • LAN obtained for overregularized verbs suggests rule-based decomposition. • Irregularized verbs elicited only a P600 relative to the correct variant. [ABSTRACT FROM AUTHOR]