This book explores verbal and non-verbal communication from a social anthropological viewpoint, drawing on ethnographic data from fieldwork in East Africa. It gives an overview of developments since the 1960s in the anthropology of language use and how these have influenced the author's thinking. The volume makes the argument that language and other forms of communication involve semiotic transactions between interlocuters; that such communicative exchanges do more than convey information; and that they give identity to the recipients of such transactions who reciprocate by defining speakers. The density and situational totality of such semiotic exchange can moreover be regarded as a kind of materiality, both in terms of their impact on social interaction and in how interlocuters interact bodily as well as verbally among themselves.