If you are not yet aware of this, Apple has introduced a new programming language called Swift in this year's WWDC, alongside the new Mac OS X Yosemite.
You ought to learn the Swift programming language sooner rather than later if you don't want to be left behind. Here are some excellent reasons that may convince you.
Swift 1 Cheat Sheet and Quick Reference
15 Free Sources To Learn Swift Programming Language - Hongkiat
Why Apple’s Swift Language Will Instantly Remake Computer Programming
iOS Swift - Migrating to Swift 3 from Swift iOS Tutorial
Airbnb testing in-app concierge feature that connects you with real people at your destination - The Next Web