Becoming fluent in a second language is not only about increasing speed and accuracy in speech. It is also about acquiring important language tools in order to deal with hesitations and other lack of fluency that occur naturally in speech, above all in connection with problems in finding the right word. In this study, it is argued that metadiscourse markers can function as such tools. By linking together the results from two studies – one regarding the development and use of metadiscourse markers and another one about the development of fluency and conversational participation – this study illustrates how the acquisition and use of metadiscourse markers play an important role in the process of maintaining fluency in speech and facilitate the conversational participation in learners/ speakers of L2 Spanish. Doctoral Thesis in Spanish at Stockholm University, Sweden 2017