Russian Historical vocative
The historical Slavic vocative has been lost in Russian, and currently can only be found in certain cases of archaic expressions. Few of those expressions, mostly of religious origin, are very common in colloquial Russian: "Боже!" (Bozhe, vocative of "Бог" Bog, "God"), often also used in expression "Боже мой!" (Bozhe moy, "My God!"), and "Господи!" (Gospodi, vocative of "Господь" Gospod', "Lord"), which can also be expressed as "Господи Иисусе!" (Gospodi Iisuse!, Iisuse vocative of "Иисус" Iisus, "Jesus"), vocative is also used in prayers, e.g. "Отче наш!" (Otche nash, "Our Father!"). These expressions are used to express strong emotions (much like English "O my God!"), and are often combined ("Господи, Боже мой"). More examples of historical vocative can be found in other Biblical quotes that are sometimes used as proverbs, e.g. "Врачу, исцелися сам" (Vrachu, istselisya sam, "Physician, heal thyself", cf. nominative "врач", vrach). Vocative forms are also used in modern Church Slavonic. The patriarch and bishops of the Russian Orthodox Church are addressed as "владыко" (vladyko, hegemon, cf. nominative "владыка", vladyka). In the latter case the vocative form is often also incorrectly used as nominative to refer to bishops and the patriarchs.
Neo-vocative
In modern colloquial Russian given names and a small family of terms often take a special "shortened" form that some linguists consider to be a reemerging vocative case. This form is applied only to
given names and nouns that end in -a and -я, which are optionally dropped in the vocative form: "Лен, где ты?" ("Lena, where are you?"). This is basically equivalent to "Лена, где ты?", the only difference being that the former version suggests a positive personal, emotional bond between the speaker and the person being addressed. Names ending in -я acquire a soft sign in this case: "Оль!" = "Оля!" ("Olga!"). In addition to given names, this form is often used with words like "мама" (mama, mom) and "папа" (papa, dad), which would be respectively "shortened" to "мам" (mam) and "пап" (pap). In plural this form is used with words such as "ребят", "девчат" (nominative: "ребята" "девчата", guys gals).
Such usage differs from historical vocative (which would be "Лено" in the example above) and is not related[citation needed] to such historical usage.