L1 Lexicon and Overcausativization in L2 English:

Acceptability Judgment by L1 Japanese Speakers

抄録

The acquisition of unaccusativity in a second language (L2) is widely recognized as challenging. In L2 English, previous studies have reported non-target-like usage of unaccusative verbs in causative constructions (e.g., *Brian fell the rock), although such errors have received limited attention compared to overpassivization. This study investigates overcausativization errors from a first language (L1) perspective. Languages differ in whether certain verbs can appear in both intransitive and transitive constructions. For example, disappear is strictly intransitive in English but has a transitive counterpart in Japanese. This lexical discrepancy may lead Japanese learners to overgeneralize L1-based verb properties to L2 English. Specifically, they may judge transitive uses of non-alternating English unaccusatives as acceptable if the corresponding verbs alternate in Japanese. To test this hypothesis, an acceptability judgment experiment was conducted with 40 Japanese-speaking learners of English. The results showed that learners failed to reject English sentences with non-alternating unaccusatives that are alternating in Japanese, while they successfully rejected those with unergatives and non-alternating unaccusatives that are also non-alternating in Japanese. These findings suggest that learners are influenced by L1 alternation patterns when interpreting L2 verb constructions, leading to overgeneralization of transitive usage in English.