This paper aims to provide a comprehensive analysis of the transformational changes observed in English business discourse over time. Employing cutting-edge methodologies such as functional linguistics, linguosynergetics, and diachronic analysis, the authors delve into the evolutionary dynamics of business communication, examining the extralinguistic factors that drive the inner discursive mechanisms of self-regulation and modification of the functional field. By highlighting these factors, the study sheds light on the complex interplay between language, society, and cognition in shaping business communication. Drawing on a rich corpus of oral and written English business discourse spanning from the late 19th century to the present day, the research reveals that the rise of new tendencies in social and political life, coupled with the historical development of British and American societies, have sparked changes in the cognitive models of structuring speech behavior in business verbal interaction. Consequently, new trends have emerged, including simplification, deregulation, deviation from communicative norms of standardized Business English, and popularization of unconventional, non-standard business rhetoric.