Abstract: The human language processing mechanism shows a remarkable robustness with different kinds of imperfect linguistic signal. The INCOMSLAV project aims at gaining insights about human retrieval of information in the mode of intercomprehension, i.e. from texts in genetically related languages not acquired through language learning. Furthermore it adds to this synchronic approach a diachronic perspective which provides the vital common denominator in establishing the extent of linguistic proximity. The languages to be analysed are chosen from the group of Slavic languages (CZ, PL, RU, BG). Whereas the possibility of intercomprehension between related languages is a generally accepted fact and the ways it functions have been studied for certain language groups, such analyses have not yet been undertaken from a systematic point of view focusing on information en- and decoding at different linguistic levels. The research programme will bring together results from the analysis of parallel corpora and from a variety of experiments with native speakers of Slavic languages and will compare them with insights of comparative historical linguistics on the relationship between Slavic languages. The results should add a cross-linguistic perspective to the question of how language users master high degrees of surprisal (due to partial incomprehensibility) and extract information from “noisy” code.