Phonetic means of the language. Phoneme distinguishability, its relation to morphological factors. The role of different phoneme functions (distinctive, constitutive). Indifferentiation of grammatical categories. Phonemes - allophones - phones. Definition of the phonemic structure of a language, quasihomonyms. Articulation differences between vowels and consonants, the role of voice. The major phonetic characteristics of Russian vowels (height, backness, roundedness; diphthongoid features of the Russian /è/) and consonants (active articulator, manner of production, voicedness vs. voicelessness, softness vs. hardness, noise consonants vs. sonorants).