The common problem many users found with Siri (iOS voice assistant) is that it can’t pronounce the names correct. Now with iOS7 Siri has taken the initiative to learn proper pronunciation from “You”.
You can simple say that That’s not how you pronounce “any name” and Siri will now ask for your help pronouncing that name. After you say the name it will present you with a few options that how it thinks you said the name. Once you save the correct pronunciation it will correctly pronounce the name next time.
The feature wasn’t mentioned during the iOS 7 keynote as its not fully baked yet, but its definitely a welcome addition.