The native speaker's grammatical competence is reflected in two types of intuition which speakers have about their native language(s) — (i) intuitions about sentence well-formedness, and (ii) intuitions about sentence structure. The word intuition is used here in a technical sense which has become stand- ardised in Linguistics: by saying that a native speaker has intuitions about the well-formedness and structure of sentences, all we are saying is that he has the ability to make judgments about whether a given sentence is well-formed or not, and about whether it has a particular structure or not. ...