Since the last century, language development of children has been a subject of study among linguists. This book presents an investigation of the early development of English as a second language by three Turkish children over a period of seven months. The main focus of the study is to examine the availability of the functional categories both within the nominal and the verbal domain in early second language development. This book is particularly important since it is one of the first studies which focuses on the acquisition of the English Article System by Turkish children. The book consists of five chapters. Chapter 1 provides the reader with a brief background on theories of first and second language acquisition. Chapter 2 discusses functional categories in first language acquisition (L1) and second language acquisition of English (L2).Chapter 3 presents the reader the morphosyntatic properties of Turkish and English within the scope of investigation. In Chapter 4, the methodology of the study is given in detail and Chapter 5 is dedicated to the discussion of findings and their implications for further studies.