Grammaticization of indexic signs: How American Sign Language expresses numerosity

Many researchers have noted that deixis in American Sign Language (ASL) is largely indexic; deictic signs such as pronouns and agreeing verbs "point to" locations associated with their referents. Number has traditionally been considered to have little or no effect on indexicality in signed languages. Thus, for purposes of simplicity, discussions of deixis and agreement in ASL have long focused on singulars. In this dissertation, I will show that reference to multiple entities results in a loss of indexicality, which I propose is due to the grammatical category number. This study focuses on indexers (i.e., signs that serve to establish a referent or referents at a location in space) and on agreeing verbs; both indexers and agreeing verbs are considered highly indexic in their singular forms. Researchers often note that agreeing verbs index the same location as their coreferential pronouns, but very little has been mentioned in the literature about how indexation applies to plural forms. I present the results from two studies: one on plural pronouns and one on plural verbs. The results from these studies have implications for the field of sign linguistics in which the linguistic status of indexic signs has recently been a highly controversial issue. The fact that plurality affects indexicality suggests that the way that pronouns and agreeing verbs use space must be at least partly linguistic because it is affected by the grammatical category number