Simon,
I understand the problem and have sympathy for foreigners when they start learning English language.
To me too, its normal to read properly either "floor" or "book" because thats the way I was thought from the very beginning. But try to explain to someone who just started learning English why is it so.
"What single letter would you replace those 'oo' with?"
It will only confuse things even further if I suggest one letter. To me it makes sense because I can speak both languages. The problem is in alphabet itself, the way we use it.
To us its normal to sound out letter "I" and pronounce word "eye" "U" and "you" or even "ewe"
We accept this as normal, we have been thought like this and think thats the only way.
Think about this words and the way you write and pronounce them, and imagine all other words are this simple:
START
STOP
SMART
One letter one sound. Simple
bob
BTW
Read this:
" A treatise on phonology: comprising a perfect alphabet for the English language; a specimen exhibition of the absurdities of our present system of orthography; Comstock's, Pitman's, and the Cincinnati alphabet, contrasted; a lecture on phonetics, by Prof. McLaine; the pamphoneticon, and recommendations of Comstock's alphabet"
http://www.archive.org/details/atreatiseonphon00leagoog
http://thenonist.com/index.php/theno..._a_phonemenon/