Learnability and grammar reorganization in L2A: against negative evidence causing the unlearning of verb movement

This paper reassesses the role of Negative Evidence (NE) in nonnative language acquisition. We argue that the grammar-building process cannot make use of NE to restructure (Interlanguage) grammars - irrespective of logical need. The empirical basis comes from White's (1991a; 1991b) study of French speakers acquiring English, where the 'Verb Movement' parameter and the particular learnability problem of 'unlearning' thematic Verb- movement were the focus. The L2ers start off assuming the L1 value of [+] Verb-movement, thus incorrectly allowing the order S V Adv O in English, and the issue is whether NE can force a switch to the [-] value, whereby S V Adv O should be excluded. While it is indisputable that the L2ers changed their linguistic behaviour as a direct consequence of their exposure to NE, the conclusion we draw is quite distinct from that of White.

Based on both the postinstruction data and an argument grounded in formal learnability theory, we show that an inherent contradiction must be imputed to the Interlanguage 'grammar' to account for the results: in addition to no longer permitting S V Adv O, the L2ers also (incorrectly) disallow S V Adv PP; to exclude the latter, the grammar must have 'un learned' base-generating Adverbs to the right of VP but other data dispute this, i.e., S V O/PP Adv is still allowed. Since natural language grammars cannot contain such inherent contradictions, we conclude that a natural language grammar could not be the source of this L2 behaviour. Our explanation is that the L2ers simply extended the *S V Adv O pattern that they were taught. In sum, there is no evidence that NE caused the L2ers to unlearn Verb-movement and hence NE did not restructure the Interlanguage grammar. Implications of this conclusion are discussed in relation to the issues of learnability and 'UG-accessibility' in L2A.