This project investigates the developmental grammar of Cypriot Greek in young individuals with Down Syndrome (CG-DS) and in children with typical language development (CG-TLD) in three specific areas: tense, agreement, and case. Similarities and differences will be compared between the two populations to determine whether DS presents acquisition stages parallel to TLD (but delayed), or whether it presents a fundamentally different development.Previous work has shown that before fully acquiring a language, children with TLD across languages are able to use only certain aspects of grammar at various stages of their language acquisition process. For example, in early development they have been argued to have an under-specified tense feature and use infinitives in environments where tensed verbs are required. A parallel stage was proposed with atypical populations like Specific Language Impairment or DS, who experience the same phenomenon though at an older age.In the only existing study on language abilities in CG-DS, it was shown that adult CG-DS and 7- to 8-year-old CG-TLD frequently perform similarly with regards to tense, agreement, and case with accuracy rates over 95%. The linguistic differences (i.e. consonant & word omissions and production of different inflectional features than those targeted) are not due to a syntactic impairment, as previously suggested for English DS. Instead, differences lie in articulatory restrictions, and use of default features rather than the targeted ones.This study will provide information on the stages of language acquisition in CG-TLD and CG-DS, with specific reference to tense, agreement, and case — the first study of its kind, for CG and beyond. Therefore, this project constitutes innovative research with regard to different stages of (a)typical language development in CG. We further aim to provide sufficient information for therapists for the development of new tools to improve linguistic performance in populations with DS.