HeyRuaHow “cén fáth” works
Cén fáth uses the indirect relative: a plus an urú in the present and future (a bhfuil, a gcaitheann) and with the irregular past forms that take one (a ndeachaigh), ar plus a séimhiú in the past of a regular verb (ar tháinig, ar fhág). Why not is cén fáth nach, and in the past cén fáth nár. To answer, say mar (because) or toisc go.
séimhiú or h urú or t-
cén fáthwhy
+athat
+fuilare
=
Cén fáth a bhfuil tú anseo?Why are you here?
cén fáthwhy
+arthat (past)
+tháinigcame
=
Cén fáth ar tháinig tú?Why did you come?
“Cén fáth” in questions
Cén fáth a bhfuil tú anseo?
Why are you here?
Cén fáth ar tháinig tú?
Why did you come?
Cén fáth nach bhfuil tú ag obair?
Why aren't you working?
Cén fáth a ndeachaigh sé abhaile?
Why did he go home?
Cén fáth a gcaitheann tú é sin?
Why do you wear that?
Cén fáth nár fhreagair tú?
Why didn't you answer?
Cén fáth?
Why?
Mar tá mé tuirseach.
Because I am tired.
Toisc go bhfuil sé déanach.
Because it is late.
Across the dialects
cén fáththe standard, everywherecad chuigeMunster and UlstertuigeConnachtcad ina thaobhMunster
Other question words
Why in Irish (cén fáth): the questions people ask
Why is it cén fáth a bhfuil and not cén fáth atá?
Cén fáth takes the indirect relative, so the verb is eclipsed after a: cén fáth a bhfuil, never atá. The same happens after cén chaoi and cén áit.
How do you say why not in Irish?
Cén fáth nach? With a verb: Cén fáth nach bhfuil tú ag teacht?, why aren't you coming? In the past: Cén fáth nár tháinig tú?
How do you answer a cén fáth question?
Start with mar and a normal sentence: Mar tá mé tuirseach. Or toisc go with an eclipsed verb: toisc go bhfuil mé tuirseach.