This dissertation is about the communicative ecologies (socio-cultural circumstances) of children who are insulated from traditional linguistic input because they are deaf and cannot hear the spoken language in their environment: “homesigners”. Unlike previous studies of child homesigners, child participants in this study have access to communicative input because they interact with other deaf adults and children who use their own homesign systems. The project uses a mixed methods design to document lexical and structural conventionalization in emerging sign systems used by deaf children and adults in Nebaj, Guatemala. Social, cognitive and linguistic sources are considered for the patterns of variation, stability and convergence that are observed in the homesign systems developed by ten focal child participants. The study contributes to ongoing cross-cultural work on how languages emerge, grow and change in temporary micro-communities of deaf and hearing people in particular cultural and social contexts.