Informal conversation is the primary context for all central processes of language. Yet it is the least studied. The many advances of traditional linguistic typology the systematic comparison of the world s languages have been based on 'isolated sentences' as data. This project will meet the challenge of working with rich conversational data. This stands to permanently remedy our skewed linguistic understanding by pioneering a systematic approach to the comparison of *language use*, to complement the comparison of language structure. This not only forges a new field of comparative linguistics, it opens up new questions of language and mind. Within mind , we include the high-order social intelligence that defines being human: our human sociality . This project will use data from social interaction to show that language is a window onto the *social mind*. A team of 6 will work on 7 languages (English, and 2 languages of Asia, Africa, and S. America), toward 3 project objectives. Objective 1 is collection of corpora of video-recorded conversation in the field. Objective 2, drawing on these corpora, is a systematic description of three defined systems in each language: (1) *repair* (of problems in speaking and understanding), (2) *reference*, and (3) *requests* (using language to get others to do things). Each system provides a window onto core aspects of human sociality: The project will focus on the relation between informational imperatives (common knowledge and perspectives) and affiliational imperatives (matters of face and social manipulation). Objective 3, drawing on Objective 2, is a detailed coding and quantitative comparison of the 3 systems across the 7 languages. This systematic comparison of systems of language use will do two things: 1. set the agenda for a new tradition in linguistics a *typology of language use* and 2. bring new evidence to bear upon interdisciplinary questions of the nature and cultural variability of human sociality.