Language is an abstract system of signs that serves for the communication between people. Language acquisition begins in the critical period of childhood and it involves all conscious and unconscious processes involved in language acquisition. The appearance of the first word most often occurs in the first year of a child's life. The acquisition of native language and foreign language is different in few areas. Children learn their native language from birth, while learning a foreign language takes place in school or specialized institutions. Learning a foreign language has a positive effect on post language development. Bilingualism is the ability to use two different languages simultaneously. Multilingualism is the ability of a person to speak two, three, four or even more languages. The emergence of bilingualism or multilingualism occurs for personal, social or political reasons. Namely, bilingualism and multilingualism have their advantages but also sometimes some disadvantages. In addition to many contents that can be found through the media or offered by the media, the motivation for language acquisition in children, together with parents are educators, stimulating environments, songs, counters, picture books, language games, but also peers. The basic aim of this paper was to examine how acquistions of two or more languages affects language development in children. The research was conducted in the form of an interview with the parents of a Croatian-French family. The obtained results are in line with expectations and it was confirmed that bilingualism or multilingualism in children has a positive effect on language, but also on the overall development of the child.