Kinds of evidence for linguistic theory

The intimate relation between general theoretical hypotheses and the empirical data which can support them is the central topic of the discussion. Data from different modes of acquisition are reviewed in the light of their general theoretical significance as different kinds of evidence for linguistic theory. Traditionally assumed correlations of properties related to the setting of the null subject parameter, availability of post-verbal subjects and modifications on the shape of the complementizer , are reinterpreted in terms of “weak” (not necessary) and “strong” (necessary) correlations on the basis of experimental acquisition data. Paths of acquisition of French and Italian clitic pronouns in different modes of acquisition are considered revealing of the possibly different analysis that clitic pronouns can be more readily subject to in different languages.