Since the 1960s, many researchers have tried to come up with explanations on how children’s language is working, how they work out the meaning of words and sentences and how they learn to communicate their own thoughts, desires and wishes. The aim of this thesis is to present why many researchers have come to the conclusion that the language acquisition process takes place so that the child analyses the system of language, making his way into the deepest realms of language so that he can start building up a system of his own by extracting rules, which are then continuously modified until the child arrives at the final conclusion, that is the correct adult form of language (Gósy & Kassai, 1990). This analyzing and building process is nicely illustrated by the mistakes children make while trying to work their way through a system in order to become “legitimate” users of it.