@nneonneo I’ve been thinking about your question, and I have an idea I would like you to please consider. I believe that finding a sentence where swapping
its/yours/theirs for
it’s/your’s/their’s does not change its meaning is
not what you need to prove that this problem is unsolvable by simple spellchecking software. Rather, I believe what you need is a sentence where that change produces a
valid sentence whose meaning is different. After all, if the meaning doesn’t change, then it wouldn’t matter how it is spelled. Only spelling changes that change meaning matter. See? —
tchrist 19 hours ago