One of the slickest updates to Windows Phone 8 is the deeper integration of voice recognition than in WP7. The previous generation phone allowed you to issue commands via voice, especially useful for making calls or starting apps – but Windows Phone 8 includes the ability to dictate emails, and there’s a whole speech SDK for developers to build great apps on. Check out Fil Alleva’s blog post, sampling 30-odd apps.
You can even hold your phone to your ear, so it sounds like you’re talking to someone else, rather than doing an Apprentice-style Shouting At Your Palm exercise.
There’s more detail about the ways to use speech in Windows Phone 8 on WPCentral.
And if you’re interested in building some more apps, then you could start here.