The fact that “Polish” and “polish” are different words is the whole point. The other commenter was saying capital letters aren’t signal, and yet.

The fact that it’s a different word makes it very different situation. It’s not the capital letter that signals this. It’s the context. Polish as a verb and Polish as a noun won’t be mistaken in a sentence. In “Polish my boots, please” we know it’s a verb, even though it starts with a capital letter. The capital letter does not ever signal meaning. That’s because a language is primarily spoken and there are no capital letters there.