Let's get past Helvetica for some more diverse typography. Capcam uses Bodoni, which was already part of iOS 6. Since many of the new interfaces are light on visual elements and use a lot of text, we can now use typography more than ever to create distinct personalities for apps. Note that some of the fonts are not preloaded on the devices, but need to be downloaded, which this article describes how to.
One tricky area will be internationalization. Many of the fonts we know and love in the western world (including Bodoni) do not support the roughly 30,000 characters required for Chinese. To illustrate the difference, Arial Unicode is one of the very few fonts that support all languages. It comes with 38,911 characters and weights in at 25 MB, and only includes regular weight. Bodoni comes with 261 characters. The best approach might be to progressively enhance typography, by relying on system fonts by default and using language specific fonts for certain countries and languages. I will spend more time with this as I start localizing Capcam.