This article discusses research into the question of whether the expectation of hereditary factors in man's unique form of communication is supported by any evidence. The research is divided into three broad categories, dealing with voice, with speech, and with language. (CFM)

Studies conducted with middle-class balanced bilinguals in "additive" environments, where both languages are prestigious, have generally reported that bilinguals showed a higher level of cognitive performance than monolinguals. In these studies, bilinguals showed higher levels of general intellectual skills, higher levels of divergent thinking, a…