Apple has been using Smalltalk for years

Sort of. You see, Objective-C has been the principal application development language at Apple for over 15 years. Objective-C was used for Cocoa programming in macOS (formerly OS X).

Since 2007, Objective-C has also been the principal mobile application development language for iOS. Swift is Apple’s anointed successor to Objective-C, but Objective-C will continue to be a foundational language at Apple for at least another decade. And that assumes Apple will ever totally replace Objective-C with Swift throughout the entire programming stack (an arduous task to be sure).

What does this have to do with Smalltalk?

Objective-C is essentially a cross between C language and Smalltalk.

You can see Smalltalk syntax front and centre in Objective-C. Message-passing between objects. Unary, binary, and keyword messages. Metaprogramming and reflection. While Objective-C also has primitive data types, most everything else is an object. The only thing missing is Smalltalk’s fabled “live coding and debugging” IDE/runtime and image persistence (which accounts for its phenomenal productivity).

Of course, you can also use Objective-C to write C language code, but in practice this is uncommon since C is a systems programming language for writing OS kernels and device drivers. This is not needed for writing desktop and mobile apps.

So when you get right down to it, Smalltalk is not as foreign as many make it out to be. The spirit behind Smalltalk has been strong for over three decades…

• Smalltalk popularized OOP in the 1980s and inspired the creation of Objective-C.
• Apple even created a Smalltalk for the Macintosh.
• Objective-C underpinned NeXTStep technology at Steve Job’s NeXT company in the late 1980s.
• Smalltalk was the centrepiece of IBM’s VisualAge enterprise initiative to replace COBOL in the early 1990s. VisualAge eventually evolved toward Java.
• The Smalltalk dialect popular for education known as Squeak was released in 1996.
• NeXTStep eventually morphed into OS X, which was released in 2001.
• Smalltalk was used by the U.S. joint military to write a million-line battle simulation program called JWARS. The JWARS project was cancelled in 2010 for budgetary reasons.
• The Pharo project began in 2008 and is the most actively evolving and growing Smalltalk today.
• Smalltalk has enjoyed more than three decades of commercial use and includes such major customers as JPMorgan, Desjardins, UBS, Florida Power & Light, Texas Instruments, Telecom Argentina, Orient Overseas Container Lines, Siemens AG, and so on. Smalltalk has always been a practical industrial language.

In one way or another, many people use Smalltalk today. Apple (Steve Jobs) was clearly a pioneer in this respect.