Language, more than any other single ability, is what distinguishes us from all other species. Children in all cultures acquire their mother tongue without the need of formal instruction. Language belongs to the class of innate abilities, such as sucking, grasping, and recognition of mother’s odor, that are too important to be relegated to our conscious awareness and “free will” (Spelke & Newport, 1997). The reason for this, many people think, seems to be that the evolution of language made human thought possible (Bickerton, 1990; Donald, 1991; K.Nelson, 1996). The centrality of language to “humanness” requires that it be part of all groups of people and not subject to cultural peculiarities. Yet language is clearly influenced by environmental factors, as indicated by the fact that although all normal children acquire language over the preschool years in much the same way all over the world, the language they learn to speak is dependent on what is spoken around them. Language is thus a characteristic that is highly affected both by humans’ general biological inheritance and by the uniqueness of the environments in which they grow up.