The Dual Language System Hypothesis is a hypothesis related to determine how children learn languages. The Dual Language System Hypothesis states that children acquire two different language systems from the beginning stages of language acquisition. Each language has its own semantic memory and the rules do not cross over from one language to the other. This hypothesis does not support the idea that bilingual children move through stages to eventually be able to differentiate the two languages. Instead it assumes that bilingual children have two different languages systems and are able to differentiate from the start of language acquisition.