Lexical conventionalization and the emergence of grammatical devices in a second generation homesign system in Peru

This dissertation is the study of a sign system used by the Máíjùnà, an indigenous community in the Peruvian Amazon. The properties of the signing community are not characteristic of either a prototypical homesigning community or a village sign language. The signing community consists of two deaf individuals (RCM and ST) and their hearing friends and family. The socio-cultural features of this sign system, which fall between that of a homesign system and a village sign language, can inform us of how community structure and the interaction between hearing and deaf signers affect language emergence. This question is explore through a grammatical analysis of RCM's system and a lexical analysis of both RCM's and ST's systems. There are two main goals of this dissertation: 1) To describe the grammatical and lexical features of the sign system and 2) To explore how the socio-cultural features of the community contribute to the emergence and maintenance of the sign system.

These goals were approached through a variety of data collection methods. To describe the grammar and the lexicon, both traditional elicitation methods and conversational data were used to support findings. The grammatical analysis focussed on argument structure and use of grammatical space in RCM's system. RCM did not produce consistent word order to mark arguments, but he did consistently use spatial modulation for this purpose. The elicitation analysis was supported by the conversational data, showing that this was not a product of the elicitation method. Data from hearing signers in the community were also analyzed. They produced highly consistent word order, but their productions of spatial modulation were less sophisticated than those of RCM, suggesting that RCM innovated the grammatical structure in his system.

The analysis of the lexicon includes detailed assessments of form and consistency between RCM and ST. An in-depth analysis of the consistency between the deaf signers and the hearing signers in the two communities was completed. Through this analysis, additional features of the lexicon are discussed, such as semantic extensions and the role of iconicity in sign form. It was found that, despite living in different villages and having only sporadic contact with each other, RCM and ST were highly consistent with each other and the hearing signers in both villages. These results were then investigated further by exploring the possible shared influences between RCM and ST in order to account for the high lexical consistency. Three experiments were conducted on iconicity, gesture and the lexicons of unrelated homesigners. These experiments showed that only a small portion of RCM's and ST's shared lexicon is likely due to these shared influences. The results suggest, then, that the two are signers of a single, multi-generation homesign system, rather than two separate homesign systems.