"The cats' men."
Translation:Fir na gcat.
I'm getting mixed up here; does this refer to the men belonging to more than one cat (since this is what the English refers to)? I thought with lenition that the na is singular?!
na is only singular for feminine nouns in the genitive - in all other situations, it's plural. Cat is masculine, and an chait is the genitive singular ("of the cat"), and na gcat is the genitive plural ("of the cats").
Yes, the men belong to more than one cat in both English and Irish. There’s no lenition involved in this noun phrase; cat is both the nominative singular form (“cat”) and the genitive plural form (“cats’”, “of cats”), and na causes eclipsis of a genitive plural.
The genitive form of a noun in English is usually fairly straightforward - for plural nouns ending in "s" like "cats" and "dogs", you just append an apostrophe to indicate the genitive.
Forming the genitive in Irish is not as straightforward. There are a number of different patterns. madra is a 4th declension noun, and the genitive is the same as the nominative, for both singular and plural. cat is a 1st declension noun, and the genitive singular of cat is cait, which is the same as the nominative plural, but the genitive plural is cat, which is the same as the nominative singular.
There are guidelines that can help you figure which declension a noun is (probably) in, and from that you can figure out what form the genitive is likely to be, but in all honesty most people just pick up the genitive forms as they go along, as you get used to the patterns.
fir na gcat - "the cats' men"/"the men of the cats"
bia na madraí - "the dogs' food"/"the food of the dogs"