I manage a team in this field presently; the answer to your question depends on whether you want to be gainfully employed doing so, or not.
Web Audio API and JUCE are the modern building blocks for mostly everything out there; if you're familiar with these, that's a really good place to start.
If you're looking for something accessible, SOUL is an excellent domain-specific scripting language that leverages JUCE underneath; see https://github.com/julianstorer for more context.
I'm not as sold on Max/MSP or Pd, though they're fun to play with for a brief moment.
Web Audio API and JUCE are the modern building blocks for mostly everything out there; if you're familiar with these, that's a really good place to start.
If you're looking for something accessible, SOUL is an excellent domain-specific scripting language that leverages JUCE underneath; see https://github.com/julianstorer for more context.
I'm not as sold on Max/MSP or Pd, though they're fun to play with for a brief moment.