The core questions are identified and discussed which have to be answered to get to a well-founded view on the syntactic structure of sentences in German: (i) Which model of linear syntax should be the point of departure for any considerations concerning the hierarchical syntax of sentences? (ii) Can there be a reductive analysis of sentences (as VP, DP/NP or PP), or are sentences a category in their own right, and what is the head of a sentence, if there is any? (iii) Which sentential features and hierarchical structures should be assumed, if one wants to cope with the most important syntactic generalizations concerning sentences? (iv) Are there any requirements on the structure of sentences coming from the interfaces of syntax? In the course of discussing these core questions, a new account of sentences as sentential phrases (SPs) is presented. The structures to be proposed are quite simple, the proposed features for valency and movement, however, are of some complexity. It is argued that the interfaces of syntax do not require specific, additional syntactic structures. This is illustrated with respect to the syntax/semantics interface and the interface to illocution.
