Additionally, (о) occurs in loanwords from Russian where the syllable is stressed in Russian. Word accent The usual rule given in grammars of Chuvash is that the last full (non-reduced) vowel of the word is stressed; if there are no full vowels, the first vowel is stressed. Reduced vowels that precede or follow a stressed full vowel are extremely short and non-prominent. One scholar, Dobrovolsky, however, hypothesises that there is in fact no stress in disyllabic words in which both vowels are reduced. Morphonology Vowel harmony Vowel harmony is the principle by which a native Chuvash word generally incorporates either exclusively back or hard vowels (а, ӑ, у, ы) and exclusively front or soft vowels (е, ӗ, ӳ, и). As such, a Chuvash suffix such as -тен means either -тан or -тен, whichever promotes vowel harmony; a notation such as -тпӗр means either -тпӑр, -тпӗр, again with vowel harmony constituting the deciding factor. Chuvash has two classes of vowels: front and back (see the table above). Vowel harmony states that words may not contain both front and back vowels. Therefore, most grammatical suffixes come in front and back forms, e.g. Шупашкарта, "in Cheboksary" but килте, "at home". Two vowels cannot occur in succession. Exceptions Vowel harmony does not apply for some invariant suffixes such as the plural ending -сем and the 3rd person (possessive or verbal) ending -ӗ, which only have a front version. It also does not occur in loanwords and in a few native Chuvash words (such as анне "mother"). In such words suffixes harmonize with the final vowel; thus Аннепе "with the mother". Compound words are considered separate words with respect to vowel harmony: vowels do not have to harmonize between members of the compound (so forms like сӗтел|пукан "furniture" are permissible). Other processes The consonant т often alternates with ч before ӗ from original *i (ят 'name' - ячӗ 'his name'). There is also an alternation between т (after consonants) and р (after vowels): тетел 'fishing net (nom.)' - dative тетел-те, but пулӑ 'fish (nom.)' - dative пулӑ-ра. Consonants Voiceless consonant sounds, if they stand in the middle and end of words become voiced: Words in english - sword, owner, peak, lunch, bouillon, window, glass, little, slice Written - hĕşĕ, huşa, pekĕ, apat, šürpe, çüreçе, kĕlençe, pĕçĕkke, katăk Pronounced - hĕžĕ, huža, pegĕ, abat, šürbe, çürejе, kĕlenje, pĕjĕkke, kadăk Geminated voiceless consonants are not voiced: ikkĕ