Editing Vocative case (section)

===Comparison===
Distinct vocative forms are assumed to have existed in all early [[Indo-European languages]] and survive in some. Here is, for example, the Indo-European word for "wolf" in various languages:
{| class="wikitable"
 ! style="width: 12em"| Language
 ! style="width: 12em"|Nominative
 ! style="width: 12em"|Vocative
 |-
 |[[Proto-Indo-European language|Proto-Indo-European]]
 |{{lang|ine-x-proto|*wl̩kʷ-o-s}}
 |{{lang|ine-x-proto|*wl̩kʷ-e}}
 |-
 |[[Sanskrit]]
 |{{lang|sa|वृकः}} ({{Transliteration|sa|vṛ́k-a-ḥ}})
 |{{lang|sa|वृक}} ({{Transliteration|sa|vṛ́k-a}})
 |-
 |[[Ancient Greek|Classical Greek]]
 |{{lang|grc|λύκ-ο-ς}} ({{Transliteration|grc|lúk-o-s}})
 |{{lang|grc|λύκ-ε}} ({{Transliteration|grc|lúk-e}})
 |-
 |[[Latin]]
 |{{lang|la|lup-u-s}}
 |{{lang|la|lup-e}}
 |-
 |[[Lithuanian language|Lithuanian]]
 |{{lang|lt|vilk-a-s}}
 |{{lang|lt|vilk-e}}
 |-
 |[[Old Church Slavonic]]
 |{{lang|cu|вльк-ъ}} ({{Transliteration|cu|vlĭk-ŭ}})
 |{{lang|cu|вльч-е}} ({{Transliteration|cu|vlĭč-e}})
|}
The elements separated with hyphens denote the stem, the so-called thematic vowel of the case and the actual suffix. In Latin, for example, the nominative case is {{lang|la|lupu'''s'''}} and the vocative case is {{lang|la|lupe}}, but the accusative case is {{lang|la|lupu'''m'''}}. The asterisks before the Proto-Indo-European words means that they are theoretical reconstructions and are not attested in a written source. The symbol ◌̩ (vertical line below) indicates a consonant serving as a vowel (it should appear directly below the "l" or "r" in these examples but may appear after them on some systems from issues of font display). All final consonants were lost in Proto-Slavic, so both the nominative and vocative Old Church Slavonic forms do not have true endings, only reflexes of the old thematic vowels.

The vocative ending changes the stem consonant in Old Church Slavonic because of the so-called First Palatalization. Most{{Citation needed|date=November 2024}} modern Slavic languages that retain the vocative case have altered the ending to avoid the change: Bulgarian {{lang|bg|вълко}} occurs far more frequently than {{lang|bg|вълче}}.