Apple (AAPL) engineers worked in secret on the vendor’s new Swift programming language, surprisingly unveiled at its recent Worldwide Developers’ Conference, for four years until delivering it to the light of day. So secretive was Swift’s development that few inside Apple beyond Chris Lattner, head of Apple’s Developer Tools unit who spearheaded the effort, even knew it existed.

Kind of gives you some added respect for Apple’s already formidable ability to keep its lip zipped on big time R&D projects, doesn’t it? Here’s what Lattner, writing on his site nondot, had to say about the Swift project:

I started work on the Swift Programming Language in July of 2010. I implemented much of the basic language structure, with only a few people knowing of its existence. A few other (amazing) people started contributing in earnest late in 2011, and it became a major focus for the Apple Developer Tools group in July 2013.

The Swift language is the product of tireless effort from a team of language experts, documentation gurus, compiler optimization ninjas, and an incredibly important internal dogfooding group who provided feedback to help refine and battle-test ideas.

For those not familiar with Apple’s new programming language, Swift emerged from several experiments to replace the venerable Object-C language platform that came along with Apple’s purchase of Steve Job’s NeXT in 1996 for $400 million, the company’s largest acquisition until its recent $3 billion purchase of Beats Electronics.

Because Swift builds on Objective-C and C languages, Apple believes the platform will feel familiar and comfortable for Objective-C code writers yet friendly enough for new programmers to step into with little to no hesitation. Lattner’s developers right now are said to be prepping Swift’s final release for a fall debut and the onslaught of people barraging it.

While Swift was built to work alongside Objective-C and C, the speculation is Apple will want the new language to be the default option as programmers adapt to it. But will Swift’s closed platform discourage developers building mobile apps for a variety of platforms from turning to it? We’ll just have to see.