Harvey Niebulski (sp?) in Seattle sings the chorus as:

Un mir zainen ale brider,
Oi, oi, schwester, brider,
Un mir zingen freileche lider,
Oi, oi, oi!

In other words,
We are all brothers,
Yes, yes, sisters, brothers,
And we sing happy songs,
Yes, yes, yes! *

*Yes, I know "Oy" or "Oi" doesn't literally translate as "yes," but I think in context of this song it works, since English doesn't really have a counterpart to "oy!"