Tough- OE toh (as in toe). In turn from OHG. Don't ask for logic. If I tried to justify the changes that occurred in the long history of these words, I would deserve to be dropped head first into the steepest cleugh around. (clewch- from 1375). Just how were words pronounced in the past? No one knows. All sorts of shifts took place. Waugh gets me too- I think I got corrected every time I said it- we has Waugh in Mod. Lit. The OED says waugh = woe is attributed to N. American Indians, but also says woe is common to Indo-Europeans. I think someone editing OED had bats in the belfry. Looking up woe I accidentally saw wlonk heading a page (= proud). Now there is a word to work into everyday conversation!