Irish anyone???

In some languages, nouns have different forms for different functions. Those forms are called grammatical cases. The process is called declension. You decline the noun to fit its function.

English nouns only have two cases: common and possessive (man / man's). The possessive is rather easy to form.

Some English pronouns have remnants of another case system: subjective and objective (I/me; he/him; she/her; we/us; they/them).

It's the same principle, but different cases and probably more (I don't speak Irish Gaelic).

The "nominative" (also called common, and is a blending of the old nominative and accusative) case, according to the article I read on Irish grammar, is used for subjects and subject complements (objects of linking verbs), direct objects, and the objects of some prepositions.

The vocative is used when addressing someone (you normally would not be talking to a peach or to sweets).

I don't know if Politically Correct is right about the specific cases he identified.

Declension

For example;

Nominative milseáin

Vocative a mhilseáin