is lupum. 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 modern Slavic languages that retain the vocative case have altered the ending to avoid the change: Bulgarian вълко occurs far more frequently than вълче. Baltic languages Lithuanian The vocative is distinct in singular and identical to the nominative in the plural, for all inflected nouns. Nouns with a nominative singular ending in -a have a vocative singular usually identically written but distinct in accentuation. In Lithuanian, the form that a given noun takes depends on its declension class and, sometimes, on its gender. There have been several changes in history, the last being the -ai ending formed between the 18th and 19th centuries. The older forms are listed under "other forms". Some nouns of the e- and a- stems declensions (both proper ones and not) are stressed differently: "aikštė": "aikšte!" (square); "tauta": "tauta!". In addition, nouns of e-stems have an ablaut of long vowel ė in nominative and short vowel e in vocative. In pronunciation, ė is close-mid vowel , and e is open-mid vowel . The vocative of diminutive nouns with the suffix -(i)ukas most frequently has no ending: broliùk "brother!", etc. A less frequent alternative is the ending -ai, which is also slightly dialectal: broliùkai, etc. Colloquially, some personal names with a masculine -(i)(j)o stem and diminutives with the suffixes -elis, -ėlis have an alternative vocative singular form characterized by a zero ending (i.e. the stem alone acts as the voc. sg.): Adõm "Adam!" in addition to Adõmai, Mýkol "Michael!" in addition to Mýkolai, vaikẽl "kid!" in addition to vaikẽli, etc. Celtic languages Goidelic languages Irish The vocative case in Irish operates in a similar fashion to Scottish Gaelic. The principal marker is the vocative particle a, which causes lenition of the initial letter. In the singular there is no special