This book offers new data on the acquisition of functional categories in early child speech. Based on longitudinal corpora of five children acquiring Modern Greek as their first language, it describes the development of single DPs consisting of definite and indefinite articles, complex DPs that require the use of multiple definite articles — possessive constructions, appositive constructions and Determiner Spreading, a form of adjectival modification — and number and case marking in nouns and definite articles. Detailed quantitative and qualitative analyses show an incremental development of the DP. The findings address the debate concerning ''maturation'' versus ''continuity''. Incremental acquisition of the DP argues in favour of a ''weak continuity'' ''approach'' to language acquisition. Whilst gradual acquisition of the DP remains unexplained within the ''Principles and Parameters Theory'', it is fully compatible within ''Minimalism'', as it is argued to result from the gradual acquisition of the features associated with the Greek DP.