The goal of the research unit is to take a close look at relative clauses within from a variety of points of view in theoretical linguistics. Although there is no single definitive way to encapsulate the phenomenon relative clauses which clearly demarcates it from related constructions and which could cover all of its many varieties, the constructions generally summarized under the term show significant similarities with each other, and differences from other construction types that call for deeper understanding.

Relative clauses are of great importance for grammatical theory. First, they are essentially a subtype of the sentence, a fundamental unit of human language, and any theoretical insight into the way sentences behave when they take the form of relative clauses tells us something very deep about human language. Furthermore, relative clauses have a large number of properties that seem to be contradictory in previous theoretical approaches, and many issues have been discussed in the linguistic literature for decades without being satisfactorily resolved. Although, there are numerous suggestions of how to analyze these constructions, no approach covers more than a part of their general properties. One prominent example of apparently contradictory properties concerns the status of the head of headed relative clauses (i.e. the word "cat" in the expression, "the cat which we saw"). Cross-linguistically, as well as in individual languages (for instance German), there is evidence for both a relative-clause-internal and a clause-external position as the underlying position. Current syntactic analyses are only able to explain these data in part. The close cooperation of the seven sub-projects of this research unit and the resulting exchange of individual knowledge from different perspectives sets out to confront such problems.

The research unit 1783 "Relative Clauses" is composed of these sub-projects together with a central administration group. The central office is the Goethe-Universität Frankfurt, while one of the projects is being conducted in cooperation with the Georg-August-Universität Göttingen.

The group employs 11 researchers and numerous student assistants, and is being funded by the Deutsche Forschungsgemeinschaft DFG for a duration of 6 years.