The contrast between written language and oral language did not really begin to attract attention until second language teaching defined as its goal the acquisition of a communicative tool rather than a literary tool. This focus on communication made necessary the distinction between language used for oral communication and language used for written communication. A problem exists in isolating criteria to define oral language, and the present paper is concerned with the isolation of these criteria. Following an examination of several definitions, a new definition is proposed, and directions for future research are proposed. The new definition of oral communication is based on a distinction between language and discourse, the former referring to a system of conventional signs, and the latter referring to actual language usage. (Author/CLK)