Английский Этимологический словарь - are

- O.E. earun (Mercian), aron (Northumbrian), see be. Also from O.N. cognates. In 17c., began to replace be, ben as first person plural present indicative in standard English. The only non-dialectal survival of be in this sense is the powers that be. But in southwest England, we be (in Devonshire us be) remains non-standard idiom as a contradictory positive ("You people aren't speaking correct English." "Oh, yes we be!")