@minusfractions
Hi :) Personally I wouldn't write a book phonetically as I once read the knife of never letting go, which has its words written phonetically, and while I thought at the time that the effect was really good, I later had a conversation with my friend who was dyslexic. This made me realise that while I liked the effect it meant that others struggled to read it which is not very fair on them. So I think if you do chose to write your story phonetically then it would be helpful to have a copy available that isn't :)
I hope this helps your decision, I really didn't mean to write that much :)