Objective-C
Smalltalk-style messaging layered on top of C — Apple's primary language for iOS and macOS before Swift.
static
compiled
since 1984
oopimperative
Objective-C was the dominant language for Apple platform development for over 30 years. Its dynamic message-passing runtime powers Cocoa and UIKit, and a vast body of iOS and macOS libraries are still written in it. Apple introduced Swift in 2014 as its successor, but Objective-C codebases remain widespread and the two languages interoperate seamlessly.