Morpho-thematic mismatches in Hebrew: What happens when morphological and thematic criteria collide?

•We examine cases of mismatch between morphological and thematic relations.•We address cases of valence changing where the derived form seems to be the base one.•The puzzle is resolved by relying on the concept of frozen lexical entries.•We offer a mechanism of morphological filling of frozen entries.•The model follows systematic guidelines and intertwines with diachronic data.

This study addresses the transitive–intransitive alternation in verb formation based on both thematic and morphological relations between words. I examine cases of puzzling mismatch between the thematic derivation of predicates via valence changing operations and the morphological form they exhibit. These are cases, where the thematic relation between two verbal instances shows that A is derived from B, while the morphological relation between them indicates that B is formed on the basis of A. To resolve this conflict, I rely on the notion of frozen lexical entries and on the historical relations between the relevant forms. I argue that while form A is indeed thematically derived from B, B existed in the lexicon as a frozen entry. Further, form A entered the actual vocabulary first and was used for the morphological formation of B.