The basic premise of this paper is that second language learning or teaching is an exercise in contrastive linguistics because learners filter and assimilate the second language through the categories and experiences represented by the first language to create situationally appropriate utterances. By selecting and exchanging information, participants in an interaction negotiate meaning, in order to establish common ground for the interpretation of their discourse. Problems in expression or comprehension are dealt with by a variety of communicative strategies such as topic avoidance, message abandonment, self-repair strategies, and collaborative strategies. Communicative interference occurs when speakers are unaware of a communicative problem and fail to express themselves appropriately or to interpret the interlocutor's meaning in a socially appropriate way. Communicative failure can occur at many levels and result in pragmatic failure in linguistic realization (the elements coded to carry messages, such as grammar and nonverbal features), communication (illocutionary value, reflecting the speaker's intention in the communication act), interaction (the system of address and turn-taking), or information (the knowledge exchanged or negotiated). Activities for developing communicative competence and for teaching and learning cultural competence are provided. (MSE)