"Twelve people are in the restaurant."
Translation:Tá dháréag sa bhialann.
Yes, it’s the personal number form of “twelve”. It’s unusual in that it’s usually lenited, and it only takes an unlenited form after an article, aon, or the ordinal céad (i.e. “first”, not “hundred”).
Can someone explain what is wrong with this construction (other than thr wrong form of 'be'):
Is dha daoine dheag sa bhialann.
Plural form of the noun after the number instead of the singular, I'd guess. And nouns are typically lenited after "dhá" -- the dialect i learned tends not to use "d(h)áréag" so that's how I do it.