The ratio of spellings to "phonemes" in English is quite high and you can have several different spellings assigned to a sound. Then you take a syllable which can have five-plus different sounds and you've got a jelly bean jar of permutations to choose from: sphinx, but why not sfynks?
I understand that one function is to differentiate words by their "etymology", distinguish "homophones", etc. Yet coverage of ambiguities is inconsistent; English orthography is the Sprint of spelling systems. I'm sure I've read one of Max Read's posts on the subject...
Let's quietly quit this madness. Here's my (revised) proposal (the slightly older one referred to by Xyl0c41n3 is here.):
I'm not a linguist, so excuse any mistakes I make in describing the sounds.