Mark Aronoff focuses on the emergence of words and lexical categories in new sign languages in this talk. Using naming experiments with groups of non-signing gesturers and signers of new languages, his research team has shown how all groups consistently distinguish between names and actions. They have also shown that emerging lexical distinctions are both cognitive and communicative in nature. They constitute common categories found in languages because they reflect the shared ways that humans interact with the world, involving self, other and mediating tools. Recorded on 2/20/2015. (#29400)