The thesis investigates conversations involving native speakers and non-nativespeakers of English. The non-native speakers partaking in the study have a welldeveloped knowledge of the foreign language. The study is particularly concernedwith the function and interactional relevance of repair strategies that interlocutorsemploy when they talk to each other. The results of the analyses highlight issuessuch as participants’ self-representations as competent speakers, the notion “nonnativeness”,and language learning, relating to current developments within conversationanalytic research on second/foreign language conversations. Comparisonsbetween non-native and native speakers are made, highlighting similarities as wellas di¡erences in participants’ use of repair strategies. The study adopts a conversation analytic framework but is also in¤uenced bystudies of second/foreign language acquisition. Conversation analytic research has,until recently, dealt with conversations involving non-native speakers who have alimited or intermediate command of the second/foreign language. Repair behavioursof advanced foreign language users are thus a little investigated area. Whereasnon-native speakers with limited experience in using the second/foreign languageoften employ repair in order to solve problems that are related to their linguisticknowledge, such as ¢nding or knowing words and constructing utterances that areunderstandable in the context in which they occur, this thesis shows how an increasedknowledge of the foreign language involves a shift in focus as repair is carriedout, i.e. repair is used to address problems of a linguistic as well as of a socialnature. Since an increased knowledge of a foreign language is accompanied by an increasein the range of jobs that repair strategies do, “doing repair” is an importantpart of the development of non-native speakers’ interactional and linguistic competence.