The findings of a detailed analysis of naturally-occurring, one-to-one 'English as a foreign language' classroom talk are presented in this thesis. Conversation analytic techniques were employed in order to elaborate the design of a chief business in which EFL participants routinely engage: attending to the adequacy of their talk. This enterprise involves the participants in focusing on the details of their mutually-created talk, and henceforth, on the target language. Repair sequences built by the EFL participants are the main interest of the study. A range of devices utilised by EFL teachers and learners in order to deal with the problematic aspects of their talk are discussed. Their design is shown to be a consequence of the local and global agendas of the talk. This thesis has highlighted the nature of the linguistic environment of the EFL classroom language learner. It has revealed the highly-organised and collaborative nature of repair work enterprises which are accomplished by EFL teachers and learners as they deal with issues related to the talk, target language and target language knowledge.