Swift is a programming language for iOS, OS X, watchOS and tvOS apps that builds on the best of C and Objective-C, without the constraints of C compatibility. Swift adopts safe programming patterns and adds modern features to make programming easier, more flexible, and more fun.
Racket (formerly PLT Scheme) is a modern programming language in the Lisp/Scheme family, suitable for a wide range of applications. It goes beyond Lisp and Scheme with dialects that support objects, types, laziness, and more.
The Objective-C language is a simple computer language designed to enable sophisticated object-oriented programming. Objective-C is defined as a small but powerful set of extensions to the standard ANSI C language.