This book examines bilingual first language acquisition (BFLA), or the development of children who hear two languages from birth. The first chapter defines BFLA and introduces the four fictional BFLA children who are examined throughout the book. The development of these children is based on real children in different language learning contexts. Chapters 2–5 follow the development of these fictional BFLA children from birth through preschool, to around age 6, showing four different possible developments of the two languages. De Houwer chronicles their language development starting with the comprehension of words, followed by babbling, one-word utterances, combining words in two-word utterances, and ending with full-sentence production, storytelling, and beginning to read. The use of the stories of these four children throughout the book helps to make BFLA more understandable as a process of development that often varies and illustrates some of the reasons for this variation. At the same time, the stories place the concepts of the book into a real-life context, which both facilitates understanding of these concepts and highlights the practical nature of the information in this book.

Through the development of these fictional children, De Houwer illustrates that differences in input, as well as differences in cues provided by parents and other caregivers to speak one or both languages, strongly affect the child’s use of the two languages. The central claim provided by De Houwer regarding BFLA children is that these differences in the amount and type of input given by the family affect how much the children develop in each language, whether they speak that language, and in what contexts. These differences in input lead to a wide range of ability in each language for each child: from being able to speak both languages fluently to being able to speak one language fluently but only understand the other language. This book demonstrates that BFLA research has important implications for SLA research, particularly with respect to the similarities between child and adult language acquisition. It provides evidence that even for children, input and other factors are important to language acquisition and that variation in language acquisition occurs in BFLA children as with adult second language learners.

The book also includes a glossary, a list of further readings at the end of every chapter (with descriptions of the main topics of these readings), and suggested questions to discuss as a class, which makes it very accessible for students as well as those with little knowledge of either the field of child language development or bilingualism. However, some of the questions would be difficult to discuss without access to a BFLA child, which may prove to be a challenge for some classes.

The final chapter clarifies an often misunderstood point of BFLA, which is that many fall into the trap of comparing these children with monolingual first language acquisition children, when in fact their patterns of learning are not expected to be the same as these children at all. At the same time, De Houwer indicates that in many ways, these BFLA children somehow do behave very much like monolingual children in terms of falling into the monolingual norms of variation throughout their development. This chapter, in particular, has significant implications for educators and policymakers alike when considering the education and development of BFLA children. Due to the importance of this chapter in terms of being able to discuss the development of BFLA children, it would perhaps be useful to read the conclusions—at least those regarding comparison to monolinguals—before reading the rest of the book, in order to keep this point in mind while reading.

Overall, the book is written in an understandable and easy-to-follow manner, particularly due to the use of the stories of the four children throughout. However, because of the length of this volume, it would perhaps be most effective when used in addition to other materials, particularly in a graduate-level course. This book would be an excellent addition to a course on bilingual child language acquisition, as it contains clearly explained information on bilingual language acquisition in an easily accessible format. As De Houwer suggests, this book would be of interest to graduate students in fields such as linguistics, education, and psychology because of its implications for language acquisition and educational policy. Additionally, the book would be a useful resource for educators and administrators interested in learning more about the implications of BFLA for their students.