The argument structure of complex predicates such as causatives and applicatives is closely associated with the functional heads that introduce core and non-core arguments: Voice, causative and applicative. These elements merge in a sentence structure at various cycles of derivation and take complements whose "size" accounts for the meaning and thematic interpretations of these arguments. This thesis shows that the variation in the meaning of causatives and applicatives is not so much due to the morphological realization of the relevant heads in these predicates (causative and applicative), but rather the complement "size" and the place where these heads are introduced. Specifically, lexical causatives result from the CAUSE head selecting for a RootP complement while syntactic causatives include two CAUSE heads taking argument-full vP as their complement and these CAUSEs are realized by separate phonological exponents at the Morphological Structure. In applicatives, Goal, Recipient or possessor interpretations may be obtained not only for non-core applied arguments in double-object constructions but for the highest external arguments of two-place predicates and also, for dative internal arguments of internally-caused events. It is argued that external arguments take on the meaning of non-core applied arguments in double-object constructions due to the different type of Voice head such as reflexive. The morphological realization of these predicates is distinct from the ones in which applied arguments represent additional, non-core elements of DOCs. The thesis shows that along with the change in morphology the syntactic structure of various types of applicatives accounts for the resulting meaning of complex predicates. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]