For those who have never programmed in Objective-C or Swift, a common question is, which should I learn first?
I would recommend learning Objective-C first – this will give you a feel for app development as it has existed since the release of the iPhone. You will learn the existing APIs and also be able to take advantage of the wealth of code/examples written in the Objective-C. If you ever need to maintain an existing app, and the odds are good, you’ll be glad you can read Obj-C code.
With a high-level understanding of Objective-C, fully immerse yourself in Swift. Swift is clearly the path going forward.