Abstract: How do young children learning different languages express linguistic arguments (actor, patient, recipient) in their speech and gestures? In this dissertation, I report a series of studies systematically investigating speech and gestures produced by adults and children speaking in three languages—English, Chinese, and Turkish, which are typologically different from each other regarding argument representation. Adults and children from three languages are asked to describe motion events. The findings suggest that there are cross-linguistic variations in adults' speech representation of arguments. However, not all those variations emerge in child speech. Unlike adults, Children from three languages omit arguments. But adhering to morphosyntactic patterns in Turkish, Turkish children omit arguments more frequently than English and Chinese children. However the deletion pattern of arguments shown in Turkish children does not look like that in Turkish adults. When gesturing, adults from three languages and English and Chinese children produce gestures to reinforce the arguments they mention in speech. In contrast, Turkish children, who omit significantly more arguments than children in the other language groups, produce gestures to convey arguments they omit in speech. Children from three languages show universal tendencies in producing gestures for recipients accompanying with speech. Universal tendencies and language-specific influences in argument representation in speech and gestures are discussed.