I will continue to update this list over time. The goal is to simply create a curated list of audio frameworks for browser, mobile, TV, and desktop devices.
Swift is Apple's new programming language and its picking up in popularity. Although the language isn't as established as Objective-C or as performant as C++, the compiler is still new and there's still a lot of cool stuff you can make.
Audio processing and synthesis
There's a new kid in the block and his name is AudioKit. AudioKit is probably the easiest way to start making an app for Mac OS X, iOS or tvOS.
JUICE is a cross-platform framework written in C++ but has a lot of classes focused around audio processing as well as wrappers that can help you port your app into both an app or a plug-in (RTAS, AudioUnit, VST, ASX).
FAUST is a functional programming language that can help you get up-and-running quickly.
Chuck is a brand new language that focuses on being sample accurate through clear and simple multi-threading. It can be used for audio creation as well as visualization. If you're a creative with an interest in creating your own, one-of-a-kind libraries or sound samples, this is a great language to learn.
Reaktor is a visual computer language created by Native Instruments. It's unique if that you can go very low-level into the stack or simply connect visual boxes and make something too like a sequencer.
Max has three core products referred to as Max, MSP, and Jitter.