One of the core ways a language expands its vocabulary is by derivation: i.e., taking an existing word and modifying it in some way to produce a different meaning (e.g., well → unwell) or to change the role it can play in a sentence (well → wellness). Words such as unwell and wellness are described as complex because of the multiple parts that contribute to their meaning and grammar (i.e., un+well, well+ness).

One long-standing question in linguistics and psychology is how do language users process complex words such as these when reading or listening? Do they break them down into their constituent parts, thus recognizing the meaning of well and that the prefix un- negates it (i.e., ‘not well’), or do they simply access the meaning of the whole word irrespective of its internal complexity; i.e., recognizing that unwell means something like sick?

This project investigates this question by recording language processing behaviour (performance on computer-based language tasks) and neural activity (the pattern of electrical signals generated in the brain while reading/listening) from native speakers of German and English at the University of Konstanz and the University of Oxford, respectively.

In addition, we apply linguistic theory and analysis of the historical development of the lexicons of German and English (as well as related languages such as Dutch) to understand the evolution of complexity in language, and the mental processes underlying that evolution.