The article considers the comparative analysis of the articulation-acoustic characteristics of the vocalism of the modern English and Russian languages (on the examples of the scientifi c discourse), taking into account combinatorial and positional changes that aff ect the characteristics of unstressed vocalism, a number of typical modifi cations in the timbre, temporal, dynamic and tonal characteristics of unstressed languages are identifi ed. Namely: the variability of the timbre features of the vowel depending on the vowel of the Russian language,to which it is assimilated by the speaker; increasing the duration of unstressed vowels; full-sounding pronunciation (absence of elision and haplology processes) of words in a weak position; insuffi cient degree of the reduction of vowels; variability and expressiveness of the tonal characteristics of unstressed vowels. The theoretical and methodological basis of the study is the scientifi c works in the fi elds of phonology, prosody, acoustic theory of speech, experimental phonetics, taking into account the problems of interaction between the components of the interfered phonetic system in the English language of Russian speakers with diff erent (high, medium and low) levels of phonetic competence. The paper uses a complex methodology of the experimental phonetic study of the prosodic features of unstressed vocalism in the English speech of the Russian language speakers. The methodology for conducting experimental phonetic research includes the use of empirical general scientifi c methods (measurement, experiment); special methods of auditory and acoustic analysis (computer-oscillographic and spectral), the method of quantitative analysis of processing the results of a phonetic experiment and the linguistic interpretation of the results of the study. The paper analyzes the quantitative indicators and the degree of these modifi cations of English unstressed vocalism in speech, taking into account the level of their phonetic competence and the experience of communicating in English.