Two origins of language evolution: Unilateral gestural language and bilateral vocal language, hypotheses from IQ test data

This report reviews sex differences in the hemispheric organization of lang uage revealed in standardized data from IQ tests. IQ test data support the notion that language is more bilaterally represented in females than in mal es. Test data also suggest that females matures faster than males. The fact orial pattern of females' IQ, which shows bilateral representation, remains the same throughout life, but the pattern of males' IQ changes from bilate ral representation at early childhood to unilateral representation at adole scence and after. Females seeking partners evolved vocal language for emoti onal and affective communication. Neotenic males were exposed to the vocal language transmitted from nursing females. Vocal language announced from th e vocal organ located at the median line was originally bilateral. Gestural language, which is announced from unilateral upper extremities, is another origin of language evolution. Use of hands and arms as language produced " Name Relation" and "Truth Value" through matching between object and hand. The hands are under contra hemispheric unilateral control of the brain. Ges tural language is the origin of unilateral hemispheric organization of lang uage.