One of our biggest frustrations with iOS devices has been the less-than-stellar stock keyboard. iOS 8 fixes that with Quicktype, a predictive, content-sensitive keyboard that learns the phrases you use most and fills them in. It's about ducking time.
At today's WWDC, Quicktype was revealed as a learns-what-you-say keyboard. So if you happen to say "turn down for what?" a lot in your texts or emails, it'll recognise when you start typing "turn down..." and offer to finish your phrase for you.
This isn't new tech -- Swiftkey users on Android devices will recognise this predictive typing. And Swiftkey is already sooooort of available on iOS; it's just buried in a note-taking app, far from the texts and emails where you want a good keyboard. Finally, finally, Apple's giving us the kind of typing tech the iPhone and iPad have been so painfully lacking.