Biological and social aspects of language development in twins.
D002675:Child, Preschool; D005191:Family Characteristics; D005260:Female; D006801:Humans; D007360:Intelligence; D007804:Language Development; D008297:Male; D011247:Pregnancy; D011578:Psycholinguistics; D011581:Psychological Tests; D012923:Social Class; D014427:Twins