If you are interested in developing applications for any Apple device, then you’ll need to learn Swift. This programming language was developed by the Cupertino company for iOS, OS X, watchOS, tvOS, and Linux development. It’s primarily inspired by C and Objective-C and C but it has extended compatibility. 

Swift is a programming language which was created by Apple inc., multi-paradigm, compiled programming language developed by Apple Inc. and the open-source community.