Determiners are grammatical elements that characterize nouns and modify them or make them refer to specific objects or actions. For example, in English: This problem is complex. " This " is a determiner that goes with " problem ". Together, they form a noun phrase. " This " indicates that " problem " refers to some problem that was raised or mentioned just before in the discourse. This entry will present the different types of determiners. Then it will explain how they are acquired by children and what types of difficulties children with language impairment have with determiners. We will not give an exhaustive description of determiners, for lack of space, but will focus on the most frequent determiners found in language acquisition. Determiners, by definition, are always attached to a noun.