This book deals with the development of morphosyntactic properties of languages in acquisition and in diachronic change, referring to empirical evidence primarily from French and other Romance languages. In our discussion, we have tried to be as specific as possible with as few grammatical technicalities as necessary, and we therefore hope that this text will be accessible not only to students of linguistics but to all those interested in historical syntax and with a basic understanding of grammar. If it should be necessary to consult introductions to generative syntax, these are readily available, e.g. Adger (2003) or Hornstein, Nunes and Grohmann (2005).

We are reporting here on some of the results of the research project Multilingualism as cause and effect of language change funded from July 1999 to June 2011 by the DFG (Deutsche Forschungsgemeinschaft – German Science Foundation) as part of the SFB (Sonderforschungsbereich Mehrsprachigkeit – Collaborative Research Center on Multilingualism), established at the University of Hamburg in 1999. This continued financial support from the DFG is gratefully acknowledged.

The researchers who worked on the project during this period are Martin Elsig (2005–11), Gisella Ferraresi (2000–2), Maria Goldbach (2001–2), Marc-Olivier Hinzelin (2002), Georg A. Kaiser (1999–2000), Jurgen M. Meisel (1999–2011, principal investigator), Anne-Kathrin Riedel-Preisler (2009–10), Esther Rinke (1999–2011, principal investigator 2008–11) and Ioanna Sitaridou (2003–4). Without our wonderful colleagues and coresearchers this book would not have been possible. Working together we learned what we now know about parametric change. We are truly grateful to all of them.

We also want to thank all those friends and colleagues in the Research Center on Multilingualism as well as Susanne E. Carroll (University of Calgary) and Robert W. Murray (University of Calgary) for their feedback on a number of issues treated in this volume.