This important and well-written book offers a timely and well-balanced review of recent research on non-native attainment. Montrul examines in great detail how age of acquisition is related to non-native outcomes, not only in L2 acquisition, but also in L1 attrition and in incomplete L1 acquisition as a result of early L2 acquisition, and how experiential factors interact with the age factor in effecting these outcomes. This book is a mine of information and is highly recommended to students of language acquisition, language attrition and bilingualism alike.

- Theo Bongaerts, University of Nijmegen,

As one of the first generative acquisition researchers who looked into the competence of heritage speaker bilingual individuals, Montrul's body of work is rightfully the standard for formal linguistic studies on Hispanic heritage speaker bilingualism. This book is the capstone to a pioneering and novel research program, initiated close to a decade ago and continuing to the present and beyond. [...] This volume is innovative in its completeness and the breadth of issues addressed. [...] This book is compulsory reading for all students and researchers who are interested in SLA, bilingualism, and L1 attrition.

- Jason Rothman, University of Iowa, in SSLA 31, 2009,

As this book has clearly demonstrated, many questions remain regarding the language development of different groups of bilinguals, and I join Montrul in calling for more longitudinal research on development in bilingual children, particularly in differences between simultaneous and early sequential bilinguals and bilinguals raised in differing political and linguistic contexts. It is clear that there are still large gaps in our understanding of age factors in bilingualism, and Montrul has done well in pointing out where more research is needed. Overall, ''Incomplete Acquisition in Bilingualism: Re-examining the age factor'' is an extensive overview of the field and a welcome contribution to the study of language acquisition and bilingualism.

- Kara T. McAlister, Arizona State University, on Linguist List 21.1599, 2010,