The two major determinants of language acquisition are the characteristics of the linguistic input, such as the structural properties of phrases and the distribution of each linguistic item, and the learner’s encounter with such an input (Kuhl, 2000; Saffran et al., 1996). The latter involves primarily the degree of exposure to a language and the age of acquisition. Information on the developmental time course of language acquisition in infancy has been gained from normal and neurologically or developmentally impaired children (Fletcher and MacWhinney, 1995). Clinical studies, together with neuroimaging investigations on bi-and multilinguals, have contributed to the identification of the neuroanatomical correlates of language production and comprehension in languages acquired before and after puberty (Abutalebi et al., 2001). However, no direct evidence concerning the neural mechanisms subserving language acquisition at any developmental stage has been forwarded. An unresolved issue pertains to how the brain regions involved in the acquisition of a second language in adulthood are related to the regions involved in processing the mother language.