This thesis investigates children's acquisition of exhaustivity across four structures: quantifiers, single questions, multiple questions and clefts. Two languages, English and German, are probed. Exhaustivity needs some sort of plural set to be mentioned without leaving out a member of that set. This dissertation provides experimental data that children start out non-exhaustively in all four structures, i.e. they start out in a singleton stage. Moreover, I show when children's transition from a singleton stage to a first exhaustivity stage occurs. I argue that the acquisition of quantification is at the heart of all of these structures. Children start showing signs of exhaustivity once they start realizing that quantification is required by these four structures. Chapter 1 contains the introduction to the theoretical background underlying the assumptions and guiding the interpretation of the data obtained in the acquisition experiment. Chapter 2 gives an overview of previous acquisition literature on exhaustivity. The results from an experimental task in chapter 3 show that exhaustivity in quantifiers and single questions is acquired significantly earlier than the exhaustivity in multiple questions and clefts in English as well as in German. It is also shown that although exhaustivity is acquired earlier in some of the structures their acquisition process is still connected through a shared feature, quantification. I argue that the delayed acquisition of exhaustivity in multiple questions is due to a difference in semantic calculation. Whereas subset relations need to be calculated for quantifiers and questions, two sets, which are not in a subset relation to each other, need to be calculated and related for multiple questions and possibly also in clefts. This two set relation is what makes exhaustivity in multiple questions harder for English and German children. The delayed acquisition of exhaustivity in clefts is attributed to an array of facts which includes a possible difficulty of a two set calculation and a possible confusion with there constructions which do not have an exhaustivity requirement amongst other potential interfering factors. Chapter 4 contains the cross-linguistic comparison of the acquisition study in chapter 3 as well as a discussion of general implications for the field of language acquisition, speech pathology and linguistic theory. Furthermore possibilities of various acquisition paths and potential trigger relations between developmental stages are discussed. Chapter 5 contains some topics that are connected to the acquisition of exhaustivity but in the interest of keeping earlier chapters clear cut and streamlined their discussion is postponed until the last chapter. One such topic is how children's mastery of focus factors into their acquiring exhaustivity since questions and clefts contain focus. Another topic which developed during the research for this thesis is whether maximality and exhaustivity differ in acquisition or not. The major thrust of the argument in chapter 5 is that maximality is different from exhaustivity and that their acquisition path differs. However, since this is not the main topic of this thesis only preliminary experimental data can be provided to support this claim. From this preliminary data we can predict that the path of acquisition of maximality may differ greatly from the path of exhaustivity. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]