Translation:You intend to listen to the story before the dinner.
Why isn't it "roimh an ndinnéar"?
Roimh an doesn't eclipse nouns beginning with 'd' or 't'.
It does eclipse nouns beginning with 'b', 'c', 'f', 'g', 'p'.
It also prefixes a 't' to feminine nouns beginning with s + vowel, sl, sn, sr.
In Gaeilge Uladh roimh an lenites where otherwise it would eclipse.
If you look up faoi in TEANGLANN.ie (or its source dictionary - Ó Donaill) you’ll see lots of ways faoi can be used. Meaning 3(d) shows its meaning as “intend.” “Want” can be expressed different ways: Ba mhaith liom ... - I would like.... Tá mé ag iarraidh ... - I want...Tá ... uaim (from ó) - I want/need.... And teastsigh can be used as in Teastaíonn cabhair uaim. - I want help. Given these take more space to explain and you’ll want to master your own dialect first, you’ll have to do that on your own from your teacher, online, or from a grammar book. Ádh mór!