Sorry if this has been answered already, but why does "am" become "a'"?
I thought it would have to do with the letter of the noun, but they both start with b so not sure why it changes?
Is this assonance? "Am bliadhna" is easy to say, but "am bhliadhna" is more difficult, "a' bhliadhna" sounds better?
Bliadhna is feminine and feminine words starting with b, p, c, g and m lenite and 'am' becomes a'.
I could easily be wrong!