Elma Nap-Kolhoff describes and discusses the results of her PhD-research on the Dutch language development of seven Turkish-Dutch children. All children in the study are raised in families of first- and second-generation immigrants to the Netherlands. At home they initially learn Turkish, but they are also regularly exposed to Dutch. The children receive most of their Dutch language input in pre-school playgroups (peuterspeelzalen), daycare centres (kinderdagverblijven) or in play-contact with Dutch speaking friends.The study described in this book deals with the Dutch language development of these children between the age of two and four. For each child, spontaneous speech data were collected at regular intervals during these two years. In the literature on childhood bilingualism, learning a second language before the age of three is often considered a form of first language acquisition. This assumption is questioned in this book. A comparison is made with monolingual children learning Dutch as their first language. In addition, the speech data are compared to Turkish adults learning Dutch as a second language. The results are analysed within the framework of a usage-based theory of language acquisition.