Projects approach these issues from different points of view. Both sides of the coin, namely what is represented and how it is represented, are subject to variation and change, and the central questions addressed by all projects are:

External and internal influences on change and variation are scrutinized across projects. The emphasis in one group of projects is on variation and on developments of representations of conceptual meaning and of grammatical form. At the same time they draw on the psycholinguistic and neurolinguistic expertise from those projects whose own focus is on the nature of mental and neural representation.

Research on storing and accessing representations and on speech processing is at an unusual advantage within this Sonderforschungsbereich, being able to draw on more sophisticated expertise in linguistic variation and development than is customary in this flourishing field. Moreover, the cooperation with neurolinguistics gives the Sonderforschungsbereich a chance to inquire into the relationship between mental representations and their implementations in the brain.