Translation:He signed the note before they knew.
Just venting, but there is absolutely no way that someone with the minimal "what is it supposed to sound like" skills such as mine would ever be able to figure this one out just by listening. Here's what I came up with, just for laughs: "Thuinneog se an nota a isa ca." I'm happy to say that, for the most part, I was able to separate the words fairly accurately, and I did get three of them right, although one without the accent. Things are looking up! :-)
Both sula and roimh can be used as prepositions, but only sula can be used as a conjunction.
Bhí is the independent past form of bí, and raibh is the dependent past form of bí. The dependent forms are used after the verbal particles an, cá, dá, go, mura, nach, ní, and sula, as well as after the relative particle a and its prepositional forms (such as in an teach ina raibh an fear, “the house that the man was in”).