What if when you stored a word in your memory the letters in the word got switched around? And, every time you access it, the letters may or may not go back in there the same way. When you try to spell the word it comes out wrong. And, when it comes out wrong it may be spelled differently than the last time you spelled it wrong. And every once in awhile you accidentally spell it correctly.
If this were true about you, people might say, "You spelled it correctly before. You are just being lazy." Or maybe, "That’s pretty dumb, you are not even misspelling it consistently."
This is how spelling can be for some people. It is something they cannot control no matter how hard they try. Since this is an invisible disability, some people have no empathy for it. I am writing this because it breaks my heart when these students are called "lazy and dumb," when in fact it has nothing to do with how hard they are trying. If this same child were blind or hearing impaired, everyone would be extremely willing to make accommodations for them (like modifying requirements for homework). But, because this child’s disability is hidden from view they get no accommodations.
If this describes your child, print this out and take it to your child’s teacher. Perhaps it will help them to think a little differently about your child’s written work! A reasonable modification for this child would be to allow misspelled words in their written work without penalty. If this accommodation isn’t made, the child will stick to using words they are pretty sure how to spell. They will not be using the full extent of their vocabulary. The quality of their written expression is limited by what they can spell....."I want to say ‘extraordinary’ but since I know I’ll spell that wrong, I’ll just use ‘good’. I think I know how to spell that!"
One last thought -- when a child is receiving remedial help for language disabilities, spelling is the last skill to improve. The reason for that is probably because when reading, the child is interpreting what is already spelled for them. But, when spelling they must come up with the spelling themselves.