Also, for anybody dealing with this specific type of bad-but-phonetic spelling with an older child, I strongly recommend you get a systematic morphemic spelling curriculum.

We've been using Apples and Pears, which is designed for children with learning disabilities (or, as the UK calls them, "learning differences") and it has done wonders for my dyslexic niece's spelling.

For kids who probably don't have a learning disability but who just need a little extra push, I've heard great things about Megawords.