Opus Modus (mentioned there) is quite notably Common Lisp

Csound (I think v3) was the first music language I played with, back in the early 90s, under DOS even. Back then, running in real-time wasn't a thing. Generate a WAV file and play it after the program finished. Later, at the end of the 90s, I remember playing with CLM/CM, in common lisp.

But the most productive experience was definitely SuperCollider. I can only recommend giving it a try. Its real-time sound synthesis architecture is great. Basically works sending timestamped OSC messages AOT (usually 0.2s). It also has a very interesting way of building up so-called SynthDefs from code into a DAG. I always wondered if a modern rewrite of the same architecture using JIT/AOT technology would be useful. But I digress... SC3 is a great platform to play with sound synthesis... Give it a try if you find the time.

There's a community in NYC called Livecode that hosts in person events for programming music and it's awesome

And at least 5 times a year someone designs a new one where it is painfully obvious that they're almost entirely unaware that anyone has ever designed one before - or if you're very lucky, maybe they've heard of ABC.

There is also literate programming for music, right? Just like Donald Knuth describes it in his literate programming approach? See for example the videos by Fauci etc. They say things like eh eh, pause then play music using items such as a pen, there is even a conductor. Very entertaining. Is that true? Or just my imagination?

Max is great.

Haskell is also a popular choice for music production and live music performance.

https://youtu.be/XYe8AKYPUYc?si=ZYP4QM5FLn00-5u6

see also https://github.com/toplap/awesome-livecoding

A few months ago I outlined a spec for a new modern programming language inspired by LilyPond I call Capo. I haven’t done anything with it yet but the idea is that it compiles to MNX, which is the (still in development) successor to MusicXML, becoming a language that could be used as a scripting language in any program that supports MNX or as a standalone text-based music tool. Thought this group might find it interesting: https://github.com/Capo-Lang/capo