TypeScript 3.6
Disclaimer: I'm currently interning at Microsoft.<p>Y'know, I can't think of many companies that have as much support for open source programming language development. Between Roslyn, TypeScript, what's left of F#, the Language Server Protocol, Chakra, V8, etc., Microsoft has a veritable powerhouse of compilers and PL development. Google has Go and Dart, but as far as I can tell, the development process is contained in Google mailing lists. Apple has Swift and LLVM and Mozilla has Rust, but each of those footprints isn't as large as the combo of .NET and TypeScript.<p>I mean, ffs, Richard Stallman is coming to speak at Microsoft. Well, Microsoft Research. But still. Stallman. That's insane.