Over the last years it has become clear that the investigation of the complexity and the dynamics of multilingual development and use needs to be approached from a new research perspective. This challenging scientific undertaking is not considered an additional approach but a replacement for the common traditional monolingual framework still applied in studying language development.By drawing on recent international research in the field of applied linguistics, this chapter provides an update of the Dynamic Model of Multilingualism (DMM) authored by Herdina and Jessner (2002) which presents the first monograph applying a CDST (complexity and dynamic systems theoretical) approach to multilingual development and use. The holistic perspective of multilingual development and use as a necessary prerequisite of the approach presented in the DMM will be unfolded by increasing the complexity in interaction of levels of inquiry in the study of third language acquisition and multilingualism.

The Cambridge Handbook of Childhood Multilingualism provides a state-of-the art view of the intra- and interdisciplinarity in linguistics, psychology, sociology, and education through a kaleidoscope of languages, countries, scholars, and cultures. The volume provides: (1) understanding that for most children multilingualism is the linguistic reality in which they grow; (2) an analysis of the effect of languages flowing from different sources, at different times and in different forms, on the uniqueness of child multilingualism processing beyond mono/bilingualism; (3) insights into diversity in the socialization of multilingual children; (4) elaboration of the triangulation of childhood, parenthood, and schooling as natural multilingualism-cultivating conditions motivated by internal and external forces; (5) an integrative approach to multilingual children’s development where the child at the center is cradled by multilingualism and languages, and (6) a focus on multilingualism as a capacity independent from mono/bilingualism. The different language typologies, in different countries and different continents, gathered in this volume tease out what is universal to childhood multilingualism as an agent of “new linguistic realities.”

The relationship between early multilingual learning and metalinguistic awareness is a particularly intriguing one. Not surprisingly, research into the effects of multilingualism on children’s linguistic development and awareness of language has attracted a lot of attention over the past years and decades as studies have found both positive effects of multilingualism on the development of metalinguistic awareness, and also facilitative effects of metalinguistic awareness on language learning. In the recent literature, metalinguistic awareness has been linked to important qualitative changes in the language and learning processes of multilinguals.