I have watched Congressman Keating since his election. He is an strong and dedicated to constituents. I am a Realtor who believes in protecting property rights of homeowners. Congressman Keating understands the housing issues such as Flood insurance, protecting the Mortgage Interest Tax Deduction and other such issues.
Judging for the closed-ness of Apple, you probably won't get much credible answer from Apple's own people. OS X and iOS are primarily written in Objective-C with some C++ in between (e.g. IOKit, WebKit, etc) and probably some C as well for the kernel stuff. However looking at Apple's software engineering jobs vacancies [1], these are also relevant programming languages at Apple: Java.
You can write universal apps which operate on both iPhone and iPad, says Kaliski. However, there are some difficulties with Objective-C programming. For one, the language is not necessarily easy to learn. Furthermore, some elements of Xcode are much different than your typical development process.