Frank Harte explains on the sleeve notes, "The title of the song is a corruption of an Irish phrase Bí i do thost or be quiet which in fact is translated in the first line of the song......Well, it's by the hush, me boys and that's to make no noise".

I've been watching the Scandi-noir series "The Bridge". which is in Swedish with subtitles, and one of the characters said something very similar to "thost" for "be quiet". I've also noticed the Swedish word for good is "bra", which is the same word in Irish, as in "Erin go bra".
It got me thinking about the possible Scandinavian influence on the Irish language, which of course would have come from the Vikings. Does anyone have any other examples of this?