Meanwhile, vim's spell checker is one of the best I have used. I recommend reading [:h spell](https://vimhelp.org/spell.txt.html#spell).

Here are some nice examples (excluding obvious edit distance based ones which it does right)

"snowbalfight" --> "snowball fight"

"unrelevant" --> "irrelevant"

"fone" --> "phone"

"the the" --> "The"

And all of this with auto capitalization if it notices you're at the start of a sentence, and stuff like handling proper nouns, punctuations, etc,.

What I find really interesting is swipe-type spell checking (its basically word prediction) on phones. That is a really cool problem to solve well. Sometimes it works like a dream and other times it's annoying. I wonder how they write those.