The central topic of the project can be worded in terms of three questions: How can we identify fixed expressions?; how can we further account for the interaction of the cognitive processes of `memorization� and `computation� in actual language use?; and how can we account for the conditions of usage that enhance inhibit the use of fixed expressions? Fixed expressions are conventionalized ways of expressing certain thoughts, and make up part of a speaker�s ability to communicate messages that sound `nativelike�, although, in principle, their actual usage can be accounted for by computational models of language processing. Hence, idioms or `frozen metaphors�, although clearly fixed expressions, do not belong to the empirical domain of the project. The conventionalized nature of fixed expressions should be accounted for by pointing out alternatives that, in principle, may serve similar semantic or pragmatic goals. By combining corpus-analytical and experimental paradigms, the project attempts to contribute to a better understanding of how fixed expressions are both understood or used, and by that to contribute to the development and validation of models/theories of knowledge of language and language use.