This article explores long head movement configurations in Breton. Its purpose is twofold. First it contributes to existing work by demonstrating that Breton long head movement is motivated by information structure. The operation of general economy principles, made sensitive to information structure, determines many of the properties of the Breton construction. Secondly, it is argued that the derivation of the Breton construction does not involve movement per se; minimality conditions on movement are not central to the derivation. Instead, the remaining properties of the construction are attributed to a semantic property of tense-aspect markers which is represented at the LF interface. This work bears on the issue of how to model the interpretive dependency between auxiliaries and main verbs and raises questions concerning the interaction between the stylistic component, information structure, and the LF interface.

In Breton, lexical subjects occur both in finite clauses and infinitival clauses. Within the Principles and Parameters model, the question arises as to how infinitival subjects can be Case-licensed, since the finite Tense element associated with Case-licensing in finite clauses is absent from infinitival clauses. Infinitival subjects are, however, preceded by some prepositional element, and previous accounts have proposed that these are Case-markers, assigning abstract Case to the subjects. However, prepositional elements also occur in controlled infinitival clauses—which have the null subject PRO—yet lexical subjects and PRO are not interchangeable. In this article, it is proposed that the crucial property associated with the Case-licensing of lexical subjects in all Breton clause types is subject agreement. This occurs not only on finite verbs, but also on the prepositional elements in infinitival clauses, which are sometimes complementizers and sometimes AgrSP heads. Clauses containing PRO, however, lack subject agreement, and hence cannot license lexical subjects.