In Colloquial Irish, I’ve heard speakers in the recordings say both “cúig bliana” and “cúig bhliana”? Is one preferred over the other? From my understanding, “cúig bliana” appears to be standard. Is “cúig bhliana” a Conamara thing?
Unfortunately, neither Gaeilge Chois Fhairrge nor An Teanga Bheo have anything to say on the subject. However, O’Siadhail does mention it briefly in his Learning Irish, saying that “five” lenites a number of special plural forms, such as “bliana”. So perhaps there is some uncertainty in that area and some people lenite “bliana”, but others don’t. Still, the word “five” itself is usually lenited in Conamara, so you’d normally say “chúig”.