Editing Openai/69186d20-2d14-8013-b9c6-c09000f173f6 (section)

=== Assistant: 2511132209ET ===
251113_2209ET

exec: modern Irish has cases, but most endings collapsed. The real action is:
* common case (nom+acc)
* genitive
* vocative
* plus preposition + pronoun fusions instead of a dative. Mutations + prepositions do half the work that endings do in Latin/German.

==== Synchronically, you can think of: ====
# Common case (historical nominative + accusative merged)
# Genitive (still productive, lots of irregularity)
# Vocative (for direct address, marked mostly by lenition + “a”)
# Dative remnants (mainly in fixed phrases & dialect; in the standard it’s basically “common case” with prepositions)

===== - Common (sg.): - an fear “the man” - chonaic mé an fear “I saw the man” =====
* Genitive (sg.): - teach an fhir “the man’s house / the house of the man”
* Vocative (sg.): - a fhir! “O man!” (lenition + voc particle a)

===== - Common (sg.): - an bhean “the woman” (article triggers lenition) =====
* Genitive (sg.): - fear na mná “the woman’s husband / the husband of the woman”
* Vocative (sg.): - a bhean! “O woman!”

Note: nominative vs accusative are identical in form, just different syntactic positions.

==== This is the one you actually feel in everyday syntax. ====

===== - Possession / “of”: - carr an fhir “the man’s car” - doras an tí “the door of the house” =====
* Noun–noun compounds (kind-of / type-of): - múinteoir Gaeilge “Irish teacher” (teacher of Irish) - leabhar gramadaí “grammar book”
* After certain prepositions: historically dative/genitive interactions; in the standard you mostly treat them as governed forms: - os comhair an tí “in front of the house” (genitive after os comhair)

===== - Masculine: often no article lenition, but genitive form changes: - fear → fir - bád → báid (many add/slenderize final) =====
* Feminine: often lenition in the genitive with article na: - bean → na mná - an chathair “the city” → lár na cathrach “the middle of the city”

You can think of “learn the genitive singular as a lexical property” for common nouns; the rules are messy but patterns emerge with practice.

==== Formally its own case, but no special ending in most nouns; you mark it like this: ====
# Prepose ''a'' (vocative particle).
# Lenite the noun if possible.
# Sometimes use lenited genitive singular in older style / certain classes, but for your purposes: just “a + lenition”.

Examples:
* Seán → a Sheáin!
* Máire → a Mháire!
* fear → a fhir!

Functionally: “hey X!”, addressing someone/something directly.

==== Historically Irish had a dative (especially after prepositions). Modern standard Irish: ====
* In most contexts, dative = common case.
* A few nouns have a distinct dative in fixed prepositional phrases, especially in dialects:

Examples you’ll see:
* ar an mbord “on the table” – in conservative Munster this contrasts with nominative an bord; elsewhere it’s just eclipsis rules.
* sa bhaile “in town / at home_ from baile, etc. Some older forms had a special “broadening” or consonant change.

For a modern learner, you can safely treat “dative” as:

: 

==== This is where Irish gets most case-y: preposition + pronoun fuse into a single inflected form. ====

Example with ''ar'' “on”:
* ar mé “on me” → orm
* ar tú “on you (sg.)” → ort
* ar sé “on him” → air
* ar sí “on her” → uirthi
* ar sinn → orainn
* ar sibh → oraibh
* ar siad → orthu

These are not just contractions, they behave like a true case paradigm of the preposition.

Same pattern for le, do, ag, ó, faoi, roimh, etc.
* le “with”: liom, leat, leis, léi, linn, libh, leo
* do “to, for”: dom, duit, dó, di, dúinn, daoibh, dóibh
* ag “at, have”: agam, agat, aige, aici, againn, agaibh, acu, etc.

This is effectively a prepositional case system.

==== 1. Nouns: - Learn the common and genitive forms; - recognize vocative (a + lenition); - be aware of a few dative fossils in set expressions. ====
# Mutations + articles: - A lot of what other IE languages do with case endings, Irish does with: - choice of article (an / na), - lenition vs eclipsis, and - noun order (head–dependent).
# Prepositional pronouns: - Treat them as mini case paradigms of each preposition; they are core grammar, not frills.

If you want to go next level, we could pick one declension (say 1st: bád, fear, páipéar type) and lay out a full but compact mini-paradigm: common sg/pl, gen sg/pl, vocative, plus the important preposition+article forms that interact with them.