AbstractThe format of business writing has significantly changed for the reason that each genre of written business discourse has its own strictly codified form. Expansion of communication fields including business communication domain affects the form of business discourse realization. In this regard, to justify the hypothesis of changing previously established speech forms functioning as a business letter genre, the present paper focuses on identification and systemizing characteristics of written documents, such as structural, lexical and stylistic markers of national and cultural specificity of English written communication. In accordance with the principles of speech activity theory and communication theory the article presents the stages of development of business contact and analyzes the structure of business writing. In the article, the structure of the business letter is presented in compliance with the intent of the addressee. The authors propose several types of exercises aimed to enhance understanding of correlation between the addressor’s intention and lexical means, as well as rubrication principles. A list of criteria for evaluating the effectiveness of written communications is also demonstrated.Theoretical interpretation of written modus of business communication based on speech activity theory and communication theory is instrumental for the analysis of constituents of written business communication act through the prism of the addressor’s communicative intentions. The approach proposed may be used in teaching practical course of the English language with the view to form universal competences of future linguists, as well as in the study of business written communication for further theoretical interpretation.