Objective-C
Hybrid of C and Smalltalk. Brad Cox + Tom Love, 1984. NeXT (Steve Jobs) acquired it in 1988 → became Apple's primary language when NeXT bought Apple in 1996. Standard iOS language until Swift in 2014.
Famous syntax: [receiver message:arg] (Smalltalk-influenced). Manual memory management early on (retain/release) → ARC (Automatic Reference Counting, 2011) made it safer. Cocoa + Cocoa Touch are the frameworks. Apple introduced Swift in 2014 → Objective-C became "legacy". Lives on in: enormous amounts of existing iOS/Mac apps, all Apple frameworks in binary form, many 10+ year old apps.