Project Summary One of the most prevalent consequences of infant deafness worldwide is delayed age of exposure to language which is known to lead to lower performance on language tasks both in the eventual first (Mayberry, 1993; Mayberry & Eichen, 1991) and second languages (Mayberry, 2007; Mayberry & Lock, 2003). The proposed studies investigate the development of argument ordering in three populations of deaf individuals who were exposed to three distinct sign languages: American Sign Language (200 years old), Vanuatu Sign Language (5 years old) and Fijian Sign Language (30 years old). Together, the three proposed studies examine the interplay of age of first exposure to language (Aim 1) and age of language community (Aim 2) on the development of argument ordering. In typical development, children with early language exposure to an established language produce the argument ordering of their environment in their early multi-word productions and rely on morphosyntactic argument marking in comprehension by the age of six years. In emerging sign languages, grammatical devices, including word order, develop over subsequent generations or cohorts as children not only acquire the language around them but create linguistic structure. The proposed studies use a picture description paradigm to elicit productive language from deaf participants who are signers of either an established language (ASL) or an emerging language (Vanuatu and Fiji). For analysis of which orders of arguments are prevalent in each population, stimuli of the production tasks are divided into event types based on transitivity and reversibility. These factors are salient in child language development and have been shown to elicit different argument ordering in emerging sign languages and homesign. Between subject analyses will compare the argument ordering of participants within each study as a function of their age of first exposure to language. Comparison across the three studies of the proposal will elucidate the effects of age of language community on the argument ordering used by deaf people in various settings. Together, the proposed studies will provide insight the creation and acquisition of language by deaf people around the world. In addition, this research project will enhance the applicant’s graduate school training, and greatly increase her chances to have a productive career as an independent researcher focusing on the effects of language deprivation and delay due to infant deafness.