One of the most enduring and significant findings from neuropsychology is the left hemisphere dominance for language processing. Studies both past and present converge to establish a widespread language network in the left peri-sylvian cortex which encompasses at least four main regions: Broca's area, within the inferior prefrontal cortex; Wernicke's area, within the posterior two-thirds of the superior temporal lobe; the anterior portion of the superior temporal lobe; and the middle prefrontal cortex (Neville and Bavelier 1998). While the language processing abilities of the left hemisphere are uncontroversial, little is known about the determinants of this left hemisphere specialization for language. Are these areas genetically determined to process linguistic information? To what extent is this organization influenced by the language experience of each individual? What role does the acoustic structure of languages play in this pattern of organization?