I've got an Android phone and I've never been able to swipe type swear words. And I'm kinda glad too. Yeah, it's a little annoying when I actually intend to type that word, but it would be way more annoying if it showed up when I didn't. I imagine it's this kind of reasoning that's behind why those words aren't available in auto-complete or swipe to type. Some people in this thread seem to be suggesting it's some kind of moral overreach or impulse to censor that's behind this behavior. I think that's an exaggeration and the real reason is the more simple and practical one that I've described.