The book presents the results of multi-parameter corpus research on Polish and English scientific discourses in the field of Linguistics. Highlighting the relevance of contextual variables (including time, culture, L1 vs. L2 language) in research framework, the study develops a discourse model of the scientific article, integrating paradigmatic, interpersonal and textual dimensions. The model is applied to investigate distribution patterns of linguistic exponents of claim-making and claim-challenging, i.e. two processes fundamental to scientific argumentation. The results show the changes which English and Polish linguistic discourses underwent between 1980 and 2010, and the extent to which English as lingua franca of modern science affects Polish L1 and English L2 linguistic discourses.