The twelve original contributions in this volume all focus on the question of whether developing grammars contain, at each stage of language acquisition, the full range of functional categories such as INFL, AGR, or COMP. The crucal evidence examined is the placement of verbs, especially in verb-second constructions. Since the position of verbal elements depends in the finiteness distinction, viz. on the presence of agreement and tense markings, the development of these phenomena is studied as well. Although there is consensus among the authors of the volume that grammars in the course of language acquisition conform at each stage to the principles of universal grammar, they disagree on whether the full repertoire of functional categories is available from early on or whether some are implemented only later. The studies presented here investigate monolingual and bilingual first language acquisition and, in one case, adult second language acquisition. The languages studied are Dutch, English, French, German, Italian, Sesotho, and Swedish.