Parent is probably not a native English speaker - I can see that behaviour in myself too. I'd typically think about some words the way I'd read them in my native language, even if I'd never actually pronounce them that way. That makes it easier to make a spelling mistake that's keeping the word close to the original spelling (for example the "s" is pretty strong when I "think" Louis, even if I would never pronounce it).

There are some benefits to that - there's no way to make a mistake with they're/their... they're two completely different words!