This study is intended to shed light on similarities and differences in terms of functional structure of the clause when modality is expressed by use of modal operators in Russian and English, in order to arrive at findings which inform, and are applicable to, the process of English language acquisition by the Russian learner. The need for the investigation was prompted by the author’s work experience in the field of English teaching, and the lack of explicit guidance in available textbooks currently used in Russian schools and institutions with regard to the particular issue highlighted. While learning the subject of Systemic Functional Linguistics, I drew parallels between the functional structures in the two languages, the purpose of which is to provide a roadmap which facilitates the learning and teaching of English modality to the Russian learner. The approach of Systemic Functional Linguistics (SFL), focusing on the metafunctions as the correspondence in the sociolinguistic message of the clause, is used as a basis for comparing the functional structures in both languages. The investigation of functional grammar features is carried out in order to spotlight  both the similarities and the differences inherent in expressing a degree of probability of an event or statement indicated, not only by the choice of an appropriate modal verb, but also its placement within the clause. The role of the social context in which the text is set is noted as significant for delivering the precise meaning of the message. Hence, the proposition will be pursued through further investigation in the field of modality, and viewed from perspectives of sociolinguistics.