Adverbial clauses: Internally rich, externally null

This paper suggests a novel syntactic treatment of adverbial clauses. The point of departure is the observation – in German and Slavic languages – that there exists an asymmetry in the complexity of subordinating elements in complement and adverbial clauses: While the former feature simplex complementizers, i.e. heads, the latter to a large extent feature complex prepositional phrases in addition to the adverbial CP. Sense can be made of this observation if adverbial clauses exhibit a structure {PP, CP} in the specifier-less framework of Chomsky (2013). The labeling algorithm suggested in that work delivers no result, i.e. structure remains exocentric in line with the spirit of suggestions regarding adjuncts more generally (Hornstein & Nunes 2008). The underlying reason for the asymmetry is thus that C-elements must be simplex to ensure that the selected complement clause is properly endowed with a syntactic category. There is no corresponding need for this in (unselected) adverbial clauses, and hence no derivational problem for Merging PP with CP which suppresses the application of the labeling algorithm.