The spelling "ough" can be pronounced eight different ways in English.
Don't panic, there aren't many words, and some of them are so arcane I usually don't bother teaching them. But let's be fairly comprehensive here.
There are five different single sounds, and three sound combinations.
- "aw" as in bought, brought, fought, nought, ought, sought, thought and wrought iron.
- "ou" as in when the bough or the drought breaks, and the UK spelling of plough (in the US regularised to plow), as well as doughty old characters, the soughing wind and a deep slough of depression.
- "oh" as in dough, furlough and though, as well as doughnut and although, if you want to count them separately.
- "ooh" as in through.
- "uh" as in thorough and borough, and names like Gainsborough, Marlborough, Peterborough and Scarborough.
- "u" plus "f" as in rough, tough and enough, plus a snake sloughing off its skin.
- "o" plus "f"* as in cough, former Australian Prime Minister Gough Whitlam and a cattle trough.
- "u" plus "p" in hiccough, though nowadays many people seem to spell this hiccup.
That's it, as far as I know. Not so terrible after all.
* The "gh" spelling of the sound "f" is also used in the word "laugh", and goes after a vowel. Before a vowel, "gh" usually represents the sound "g" as in "Afghan", "ghost", "spaghetti" and "yoghurt".