The ever-increasing spread of English as the language of global communication leads to ever-increasing demand for learning it among adult populations of non-English-speaking countries. If such people did not have a chance of acquiring English during their school or university years but urgently need it for professional or personal purposes, they have no other choice but to go and learn it at courses offered by numerous commercial language schools and centers. In post-Communist countries, such as Ukraine, commercial language schools and centers are responsible for English language training of the majority of adults learning that language after their secondary or tertiary school studies. They also serve the needs of many high and higher schools' students who, due to various reasons, are not satisfied with learning English at their educational institutions. However, despite the importance and spread of this specific type of language education, its pedagogical and methodological foundations have hardly been developed at all. The present article is an attempt of partly filling this gap in pedagogy and methodology of English language education in non-English-speaking countries. The paper develops some theoretical underpinnings of that kind of education in the form of six principles underlying the organization of commercial English language courses, formulating their goals, selecting the learning contents, and choosing the methods of teaching and learning. The practical consequences of adopting the six suggested principles are outlined.