Exceptionality and derived environment effects: a comparison of Korean and Turkish

Morphologically derived environment effects (MDEEs) are well-known examples where phonotactic patterns in the lexicon mismatch with what is allowed at morphological boundaries – alternations. Analyses of MDEEs usually assume that the alternation is morphologically general, and that the sequences ‘repaired’ across morpheme boundaries are phonotactically well-formed in the lexicon. This paper examines the phonotactic patterns in the lexicon of two languages with MDEEs: Korean palatalisation and Turkish velar deletion. I show that Korean heteromorphemic sequences that undergo palatalisation are underattested in the lexicon. A computational learner learns a markedness constraint that drives palatalisation, suggesting a pattern of exceptional non-undergoing. This contrasts with Turkish, where the relevant constraint motivating velar deletion at the morpheme boundary is unavailable from phonotactic learning, and where the alternation is an example of exceptional triggering. These results indicate that MDEEs are not a unitary phenomenon, highlighting the need to examine these patterns in closer quantitative detail.