Different THAN/ different FROM/ different TO......

Nobody notices if you use one and its wrong in normal speech. But if you need it for a class or so my best guess would be different from unless its a comparison. Like he is more different than her. In that case different than would be used.

I don't know about the UK, but I'd never use "different to," in speech or writing.

I agree with Wy. "Different to" is an expression I've never heard and would never use.

"Different from" is considered acceptable usage under all circumstances. Up until fairly recently, "different than" was not correct usage. The expression has gained some acceptance in certain circumstances, but I prefer and continue to use "different from."

I've been using "different from" all my life, and didn't know there were others! Roberta, would you care to explain the circumstances? I'm hazarding a guess but this is what I gather from their usage:

"I'm different than you."
It sounds like I'm comparing who's more different - you or me.

However if I intend to emphasize the differences between you and me, then I would say: "I'm different from you."

Sarius, I, too, have always used different from. Always. I nearly fell over in a dead faint when I found a reliable source offering "different than" as correct usage in some cases. Here's what the source says:

"Although "different from" is normally preferred, "different than" is acceptable in order to avoid sentences like "I view the matter in a different way from the way in which you do."

I may contact the author of the source. "Different than" doesn't sit right with me.

BTW, the Chicago Manual of Style says: The phrasing "different from" is generally preferable to "different than," but sometimes the adverbial phrase "differently than" is all but required. She described that scene differently than he did.

I think that if the best you can do is "different than." you should think about rewriting the sentence... of course, I rethink and rewrite a lot.