Translation:Dublin is the capital city of the Republic of Ireland.
This is an example which contains a noun that is “nominative in form, genitive in function”. The reason for it in this case is that Irish doesn’t express successive nouns in genitive form when the second noun is definite; only the second noun in such a genitive “chain” takes the genitive form (e.g. Éireann rather than Éire in this case). Despite the nominative form of Poblacht, because of its genitive function, it becomes lenited as genitive nouns normally would, as you’d observed.
Yes, in English we don’t use the definite article with names (He is Sean) and sometimes with unique job titles (He is Chairman of the Board) and sometimes when specifying other unique roles (Paris is capital of France). My impression is that the rules governing which nouns have artices in “príomhchathair Phoblacht na hÉireann” are different - more like: “a noun can be specified by a genitive or an article (an, na etc) but not both”. But I still have not worked out why we usually see Éire without the definite article but Éireann with the definite article na.
In English the rule is that a noun may never be qualified by more than one “determiner”. A “determiner” includes
- an article or possessive pronoun - “the cat”, “my cat”, “a cat” but NOT “a my cat” or “the your cat” or “any my cat”
- a genitive ending in -s
In “the ship’s captain”, the word “ship” has the sole determiner “the” and the word “captain” has the sole determiner “ship’s”.
The difference in Irish is that the genitive usually or always comes after its noun, and so superficially looks more like the “of” genitive in English, which in English in NOT a determiner: “THE captain of the ship”.
When the subject of an identificational copular statement is a proper name (e.g. Baile Átha Cliath in this sentence), then the sentence order is Is + subcomplement + subject + complement. The é is this sentence’s subcomplement, and it provides separation between is and the proper name, since is isn’t allowed to come directly before a definite noun (such as a proper name).
Note that the é should be í, since príomhchathair is feminine.
No i'm not talking about the pronoun i understand why it is there and that it should be there. What i'm talking about is that it says: Is é BÁC príomhchathair PnÉ = Dublin is the capital city of the RoI, but when compare it with a simpler (is dochtúir é an fear - the man is a doctor) it is set up the same. By the simpler, the structure is: Is "y" é/í "x" = x is y, but by the complex, the structure is: Is é/í "x" "y" = x is y. And that's where I'm confused, because given the structure by this simpler i would then say this sentence translates to: the capital city of the RoI is Dublin, not the other way around.
Technically, the Irish (Gaelic) for that would be different. Also there are political nuances. Many in the Republican movement would contend that the 26-county state called "The Republic of Ireland" is a different animal to an or the Irish Republic. Also in international law no entity bearing the name "The Irish Republic" exists or is recognised. It is just a shorthand in the vernacular.
And Ireland and both the terms previously discussed are most definitely not interchangeable. Ireland refers to the whole island and to all-Ireland entities such as rugby and cricket teams and churches. That is quite distinct from the "Republic of Ireland".