The existence of functional projections in a particular language may be motivated on the basis of different kinds of evidence, relating both to X⁰/head-level items and also phrasal categories. Frequently it is the occurrence of independent words (heads) or inflectional morphemes with primarily functional-grammatical rather than lexical-descriptive properties that is presented as evidence for the occurrence of functional projections in a language, especially when the distribution of such elements seems linked to certai…