In this paper we describe how children acquire foreign language. It is well known that the very early age is a most suitable time to start foreign language learning. This is partly because up to the certain age every child learns foreign language as a part of a natural process. For our research we had to study theories of language learning, predominantly nativists’ theory, where Chomsky argues that there is an innate factor, known as Language Acquisition Device, and further development made by Lennenberg, but also empiricists – behaviourists’ theory upholding the element of imitating (Skinner) and cognitivists’ theory that argues that cognition precedes the language development (Bruner, Piaget, Vygotsky, Sapir–Whorf). We are giving an overv...