Contrastive linguistics and micro-variation

This article deals with a very general problem, namely the origin of the well-known distinction between dialectal and typological variation. It is argued that the fact that the possible grammatical choices are more restricted within a dialectal domain is not due to a supposed principled difference in the parameters that rule variation. Rather, they are a function of the originally unitary lexicon dialects share. If language variation is essentially located in the functional items, and they are derived from the same lexicon, then they will share some core properties that make dialectal variation so restricted. I propose that the fact that the lexicon is similar can give us clues about the internal structure of syntactically complex elements which are represented by a single word, like quantifiers, wh-items, modal verbs, etc. Within a homogenous domain, structural complexity correlates with a higher number of lexical roots: the higher the number of the lexical roots found, the more complex internal structure the functional item will display.