The main aim of the research reported in this thesis is to provide a practical contribution to the assessment of language problems in brain-damaged patients, e.g. patients suffering from the consequences of a stroke, traumatic brain damage or brain tumour. A broad clinical populations is studied, since apart from aphasics also right-brain-damaged (RBD) patients were included. In the latter case the main language problems are not confined to the linguistic levels of verbal behaviour as in aphasia, but affect the more cognitive and pragmatic aspects of communication. To put it another way, they spread from the level of language functions (phonology, syntaxis, word finding) to the level of participation. Existing Dutch tests for verbal behaviour (Aachen Aphasia Test, Boston Naming Test, Metaphor task) were evaluated and if necessary adjusted and elaborated in order to answer the specific questions that arose from the clinical setting. Besides the emphasis on the practical assessment of language problems we tried to solve a number of fundamental issues dealing with the communicative problems in RBD-patients and the role of the right hemi-sphere in normal language processing.