The majority of scientists in the field of linguistics and pedagogy consider that a good mastering of a foreign language is impossible without a proper learning of pronunciation, especially in case of languages the orthography of which is based on the ethimological principle that presupposes the spelling-pronunciation discrepancy, English being one of such languages. In order to achieve this goal, it is necessary to respect the principle of the conscious mastering of the studied material, which is possible on the basis of comparative contrastive analysis with the native language. From this point of view, speech sound of the two languages (native and foreign) are divided into same (completely corresponding in both languages), different (existing only in one of the languages) and similar (corresponding in major features but different in secondary characteristics). Scientists affirm that the third category is the most difficult to learn. English affricates belong namely to it. In this article, Roumanian-speaking students’ mistakes in these sounds are examined in the context of their general mistakes in pronunciation and other language aspects. To avoid and correct such mistakes, a set of methods is suggested.