This is one of these dumb "I don't understand development because my other child is odd" questions. (DD is an exceptional speller and always has been.)
DS7's verbal IQ is 150 and he reads hundreds of pages a week, way above grade level. His written work is pretty good, but maybe a year above grade. Handwriting looks messy to me, but his teacher says it's good. Personally, I'd say it's average for grade.
Here's the thing. He is a fantastic verbal speller. If we play "spelling bee," he can correctly spell words far above grade level, like "functionality" and "irresponsible" (I made those up, but similar). Written work is much less accurate. In particular, he leaves letters out or gets them out of order in weird ways. In the past week I've seen "enouhg," "questoin," and "fried" for "friend." It is probably one word per paragraph, and sometimes a very easy word (not "cat," but could be "shoudl" for "should"). He always gets 100% on his spelling tests, but they are super easy. He also does correctly spell harder words right pretty often, so it's weirdly inconsistent.
DD would never have done anything like this (if she misspells, it is something like "defanitely" or "embarass") so I have no idea if this is a) typical and b) typical for a child with these very advanced verbal skills. He is certainly not dyslexic, but given the excellent verbal spelling, is something happening between brain and paper, or is this just normal for a child still developing writing skills?
