Though the NIE-al pronunciation is common in Ireland, the only legit Irish (language) pronunciation is NEE-al. NIE-al is actually an English pronunciation.
― Anonymous User 8/18/2009
1
It's pronounced Ni as in it would rhyme with eye, and finished all as in it would rhyme with ball: Ni - all . It's a very popular name in the North and South of Ireland, I once watched a documentary that claimed it is one of only 4 male names that are originally Irish as most other popular Irish Male names descend from somewhere else. Famous Nialls are Niall Quinn, famous football player and manager of Sunderland FC, and Niall McDevitt, the Southern Irish Poet. Both you can Google.