Virtually all of the audio plugin development is done in low-level languages like C++ to keep the illusion of real-time as close to being true as possible. Recently though, ROLI released a new programming language for audio processing. It's called SOUL , a less convoluted way of designing audio processing software. I took a look at it and in no time, created this simple detuned sinewave synth. Sure, it is pretty much based on the examples but it took only a couple of hours to implement. If I would have done this in C++, a week would not have been enough. SOUL provides abstractions for inputs and outputs, lots of ready-made functions for waveforms, phases, and time-to-frequency domain conversions. It's pretty new though and examples, editor support, and proper documentation is still lacking. I plan to keep an eye on the development and will return with some more demanding audio processing later on. You can try the example on the browser by copy-pasting it to the browser play...
Notes about what I do