Primitive Irish

Sorry if I am off-topic here, but does anyone know the Primitive Irish (i.e. as spoken about Julius Caesar's time) forms of the Irish surnames Niall and Néill? (Similar to, e.g., the old Irish king name Laoghaire looks like it came from *Loigarjos" or similar, and the river name Boyne / Bóinn is recorded in Ancient Greek as Βουουινδα = Buwinda.