The aim of this dissertation is to develop a framework of functional structure that ensures that the representation of any phrase is only as large as necessary to capture the syntactic relations relevant to it. I argue that the success of this project requires the elimination of null functional heads from the lexicon. Rather, I propose that null functional heads and their projections are dynamically created during the derivation as an extension of the projection of lexical items (i.e. lexical heads and overt functional heads). To this end, I make two proposals. Firstly, I argue that the featural specifications of lexical items are more extensive and have a more complex structure than previously thought. Secondly, I refine Giorgi and...