Pronunciation and orthography vary in many cases, not simple at all. Unless you already come from a germanic language, then it's relatively easy.
Even if you know the origins of the word, you still have to guess: facade is pronounced correctly, but the pronunciation of Uranus was apparently left up to a 5-year old to decide. Kindergarten and doppelganger are pronounced the German way, angst and flak aren't. The non-loanwords are somehow as inconsistent, after pronunciation changed but the spelling was preserved (and the other way around). For an unknown word you can come up with reasonable guesses, but they might be totally wrong. The only thing that makes us good English speakers is extensive exposure to English media.
What's the relationship?