As noted in the comment thread on a recent posting, the orthography (the way we write a word) and the pronunciation (the way we say a word) often have no seeming relationship to each other. Nor, when we do just a little bit of research, is the orthography/pronunciation relationship always the same. Sometimes "ancient" pronunciation exists in words whose spelling has been changed. Sometimes we pronounce words differently now even though we maintain an older written version of a word. Let's look at the "-ough" construction in English.
Tough, rough, enough--the -ough is pronounced as if spelled uff. (Interesting note: there is a word enow, an archaic form of enough, used by Shakespeare. It apparently didn't "take" and we are still stuck with enough instead.)
Cough--the -ough is pronounced as if spelled off.
Borough, thorough, dough--the -ough is pronounced as if spelled oh.
Through--pronounced as if spelled ooh.
Ought, bought,fought, brought, sought, thought--pronounced as if spelled awt.
Slough, bough, drought--pronounced as if spelled ow
Further complicating things is the -aught construction, giving us caught, taught and daughter pronounced as if the -aught is awt, and draught pronounced as draft, with the -aught as aft.
If you delve into the history of the words above you will not find the -ought or -aught spellings in the origins of the words. It was someone's attempt at standardizing the spelling, but didn't take into consideration the different pronunciation that remained.
Many people have suggested that we need to standardize our spelling to conform to the way that words are pronounced. This is problematic for two reasons: 1) American English is pronounced differently in many instances depending on geographic location in the country and 2) we could well lose the historical trail of the original roots and meanings of words.
There have been movements before to standardize English spelling; they have all basically failed. For now we are all going to have to grin and bear it, and make close friends with a dictionary.