Morphological generalization in heritage speakers: The Turkish aorist

Heritage speakers (HS) have been shown to experience difficulties with inflectional morphology (particularly with irregular morphology) and to frequently overapply regular morphology. The present study seeks to get further insight into the inflectional processes of HS by investigating how these are generalized to nonce words in language production, the first study of this kind for heritage Turkish. We specifically examined morphological generalization processes in the Turkish aorist which – unusual for this language – includes both regular and irregular forms. A written elicited-production experiment containing nonce verbs with varying degrees of similarity to existing verbs was administered to Turkish HS and native monolingually-raised Turkish speakers (MS). We also explored how well a formal model that was trained on a large lexical corpus of Turkish matches the human speakers’ performance. Our main finding is that HS employ both similarity-based and rule-based mechanisms for morphological generalization of the Turkish aorist, with subtle differences to the way these mechanisms are applied by Turkish MS.