Language comprehension is a fundamentally dynamic process, where incoming speech information interfaces with two markedly different neuro-cognitive processing systems a left lateralised fronto-temporal system that is critical for linguistic processes of morphological and syntactic analysis, and a distributed bi-hemispheric system that supports semantic and pragmatic interpretation. This view of the neurocognitive language system has emerged from interdisciplinary research focusing mainly on English. The research proposed here will take our understanding of these systems to a new level of specificity in terms of the spatio-temporal pattern of different language processing procedures across the brain, while achieving a new level of generality by conducting parallel investigations in three contrasting languages. The first strand (English) will use behavioural and neuro-imaging methods (fMRI, MEG) to analyse the neural networks engaged by different types of morpho-lexical complexity. We will contrast specifically linguistic forms of complexity (derivational and inflectional morphology, argument structure, etc.) with more general sources of complexity reflecting on-line competition between different lexical and phrasal interpretations. Research in English suggests that these engage different processing systems across the two hemispheres. The second strand (Polish) examines the neural dynamics of the same sources of processing complexity in a morphologically much richer language, but sharing with English the same concatenative word-formation mechanisms. The third strand will analyse neural responses to processing complexity in the radically different morpho-lexical context of Arabic, where the fundamental mechanism of word formation is non-concatenative, and where key grammatical morphemes serve multiple linguistic functions. These cross-linguistic neuro-cognitive comparisons will provide important new information about the relationship between language and the brain.