Constructing Subject-Verb Agreement in Speech: The Role of Semantic and Morphological Factors

A sentence completion task, first introduced by Bock and Miller (1991) with English speakers, is employed here with Italian to explore the issue of interactivity of different levels of processing in sentence production. In a series of three experiments, we tested the effects of three variables on the number of subject-verb agreement errors. Like Bock and Miller, we found that mismatching singular and plural features between the subject head noun and a local noun in a complex NP increased the number of errors. It was also found that ambiguous morphophonological marking on the subject noun increased errors. The most striking result was that the preferred interpretation of the complex NP had a significant influence. Singular heads, normally taken to denote several tokens, such as the label on the bottles, tend to induce incorrect plural verb completions. This is in contrast to the findings for English speakers and raises the question as to whether the construction of subject-verb agreement is a purely syntactic process in all languages. A modified version of a model of syntactic encoding (Kempen & Hoenkamp, 1987) is proposed that can satisfactorily deal with the number mismatching effect and crucially the presence/absence of semantic effects on verbal agreement in different languages.