Why is it "ag an trá" and not "ag an dtrá"? Doesn't " ag" cause eclipsis?
It is because of the DeNTaLS DoTS rule. "t" doesn't eclipse when it is directly preceded by "n". A full explanation of this rule can be found in the notes of the Eclipsis skill :)
But, to elaborate, in Munster Irish it does eclipse in that position.
Thanks, I missed that before
In Ulster Irish, ag an X lenites X; however, ag an trá would still be left alone because trá begins with one of D, S, and T.