Words have grammar: Investigating semantic and syntactic aspects of word knowledge for verbs

This study takes an integrated approach to the investigation of word knowledge using tools from vocabulary and grammar acquisition research. Tests of vocabulary size, depth of word knowledge and syntactic recognition were administered to 63 adult learners enrolled in intermediate and advanced level ESL classes. Scores of vocabulary size from the Vocabulary Levels Test (Nation, 2001) were compared with scores on the Vocabulary Knowledge Scale (Wesche and Paribakht, 1996), a measure that required learners to demonstrate semantic and grammatical knowledge of 32 verbs from four lexical frequency levels. Grammatical knowledge of the same set of verbs was further explored in terms of four syntactic features using a grammaticality judgement test. The results indicate that learners demonstrated knowledge of fewer words than predicted by their vocabulary size, particularly for higher frequency words. Furthermore, learners were more likely to judge a sentence accurately if they were also familiar with the meaning of the verb. This held true in the case of three of the four syntactic features investigated. However, learners were unable to form grammatical sentences with many of the verbs they knew semantically. In contrast to the variation in the results for syntactic accuracy, learners consistently expressed greater confidence in their judgements of sentences containing better known and higher frequency verbs. These findings have implications for applying a lexical frequency approach and an expanded definition of word knowledge in the description of lexical competence in vocabulary acquisition research, as well as incorporating vocabulary measures in second language acquisition studies more generally.