Siri will intelligently learn names to pronounce them correctly in iOS 7. And if it fails you can teach it the correct sound.
9to5mac has discovered, while using an iOS 7 beta, that Siri now asks you if it’s pronouncing names right. If not you can say, “that’s not how you pronounce [name]” and it’ll ask you to say it correctly. Then you can select from a few options the one closest to what you said so Siri gets it right from then on.
Siri is also a broader virtual assistant and now even turns on the LED light if you ask. [Source: 9to5mac]