Weak Heads at the Interface: A View from Temporal Adverbial Clauses

This paper proposes that weak heads in Chomsky’s (2015) sense are not only syntactically weak (i.e., unable to provide a label on their own), but also morpho-phonologically weak. To illustrate how this works, this paper examines temporal adverbial clauses (TACs) in Japanese, showing that the presence/absence of what we call Geis-ambiguity in Japanese TACs correlates with the presence/absence of yori ‘than’ in the clauses. Based on Miyamoto’s (1996) argument that this ambiguity arises due to operator movement, we propose that there is a covert weak head which hosts the relevant operator in its specifier. Crucially, the weak head in question can only be present in the presence of its morpho-phonological host, i.e., yori. We further demonstrate that this covert weak head, unlike an overt noun, cannot be referred to by a null resumptive element, and suggest that the weakness in the labeling sense could potentially lead to weakness at LF.