User:Sashay23

Chuvash declension
Both variants of the genitive plural -сен / -сенӗн are used.

Suffixes depend on the shape of the stem, and on vowel harmony:

Stem shapes
main shapes
 * consonant-final (except resonants)
 * = в, й, к, п, с, ҫ, т, х, ч, ш
 * resonant-final
 * = р, л, м, н
 * vowel-final (except reduced vowels and high vowels in some words)
 * = а, е
 * reduced-final
 * = ӑ, ӗ

other exceptions (see text below)
 * high-final
 * = у, ӳ (become -ӑв- and -ӗв- before a vowel-initial suffix)
 * geminating consonant-final
 * = any consonant (geminates the final consonant when the word is suffixed in dat-acc or gen cases)

In the genitive and dative-accusative cases, some nouns ending in -у and -ӳ were changed to -ӑв and -ӗв (ҫыру → ҫырӑван, ҫырӑва, but ҫырура; пӳ → пӗвен, пӗве, but пӳре). In nouns ending in -ӑ and -ĕ, the last vowel simply deletes and causes the last consonant to geminate (пулӑ 'fish' > пуллан). Nouns ending in consonants sometimes also geminate the last letter (ҫын 'man' → ҫыннан).

Vowel harmony
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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).

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).