OUGH!

I've read Pilgrim's Progress several times and still can't remember how to pronounce slough, as in Slough of Despond. Does it rhyme with cow? Do? Cuff?

No letter combination in English is more frustrating than ough. It can be pronounced at least 9 different ways:

rough (uff)
through (oo)
bough (ow)
cough (off)
dough (oh)
hiccough (up)
fought (aw)
Poughkeepsie (uh)
Coughlin (og)

Slough causes problems because it's pronounced different ways, depending on meaning. Slough pronounced sluff is the term for shedding skin, like snakes do. Slough meaning wet, swampy ground can be pronounced either sloo or slou. Dictionary.com prefers slou, while the American Heritage Dictionary prefers sloo. I'm going with sloo too.