This volume brings together chapters written by specialists in North America, Europe and Brazil. It includes original research about the acquisition (L1, bilingualism) and acquisition/ learning (L2 or L3) of dialects of Brazilian and European Portuguese. In an effort to maximize volume cohesion, the emphasis has been on contributions that present studies exploring both empirical/experimental and theoretical aspects of the acquisition of syntax, and its interfaces with morphology, with semantics/pragmatics, and with language change.