Do languages ever get new cases?

Question

In my education, I've learned about a lot of languages whose case systems have atrophied, especially from PIE. Wikipedia had a reference to The Evolution of Case Systems for Marking Event Structure, but that was focused on language games (abstract below):

Case has fascinated linguists for centuries without however revealing its most important secrets. This paper offers operational explanations for case through language game experiments in which autonomous agents describe real-world events to each other. The experiments demonstrate (a) why a language may develop a case system, (b) how a population can self-organize a case system, and (c) why and how an existing case system may take on new functions in a language.

So, has any modern language added a case? I'm most curious if, for example, the grandparent generation lacks a case the current generation has.

Answer 1

Yes. One well-known example of a case emerging as we write is the Russian neo-vocative:

In modern colloquial Russian given names and a small family of terms often take a special "shortened" form that some linguists consider a reemerging vocative case.[4] 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 that end 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 to such historical usage.

In this case, of course, the parent does not have the case, but the historic language by coincidence did.

An older but very complete example is Ossetian.

Ossetic has also entirely lost its original IE case paradigm system, in which suffixes combined number and case in a single affix. Ossetic has instead innovated an almost entirely new system with a discrete number suffix followed by one of nine case suffixes (again, mostly unknown in IE).

See also the recent more general question: Languages that are gaining morphological distinctions