Beir is one of those words in Irish that has several meanings, depending on its context.

Actually, I'm looking at the words in "Croch Suas E" now, and they're:

Bheir mí óró, bhean ó
Bheir mí óró, bhean í
Bheir mí óró, bhean ó hó
Is mé tá bhrónach is tú i m'dhith

Now, this sounds like Northern Irish to me - maybe Donegal, or maybe one of those places in Down or Antrim where some Irish remains. I mean, I'd always thought the last line was "Is mé atá brónach, is tú i mo dhiadh", meaning "I am the sorrowful one, and you left behind me", whereas if the version here is correct, it's "I am the sorrowful one, while I lack you".

The next verse, "Is iomaí oíche..." translates as "Many's the night, cold and wet , I made a visit, and I on my own; Or that I came into this place, Where was the bright love of my bosom".

And the verse after that (I mo chláirseach...) means: "in my harp there was no music, in my... there was no spirit; or since you somethinged you your secret and i got knowledge of my poem". Of course, both "secret" and (unusually) "poem" can be used to mean "darling", so we're no further than we were. I give up. Maybe someone more knowledgeable of the particular song and dialect can help here.