In the talk I will first present a functionalist, usage-based approach to the notions of grammaticality and acceptability. After this I will present and discuss two sets of acceptability judgment and reading time experiments with sentence intertwining in Danish. Sentence intertwining is a type of extraction where a non-wh constituent is fronted from a subordinate clause to a matrix clause. This is possible in Danish, although there appear to be some constraints. The experiments investigate some of these constraints.