The Spelling-Checker does not check every mistake. Here’s a poem to illustrate this. Try it in a word processor and see.
I Have a Spelling Checker
(Anonymous)
I halve a spelling checker;
It came with my pea sea.
It plainly marks four my revue
Mistakes I dew not sea.
I've sent this message threw it,
And I'm shore pleased to no
It's letter perfect in its weigh;
My checker tolled me sew.
