For personal preference, assuming I didn't have to worry about getting a job, Lisp no question.

Otherwise, I'd have to go with C++.

I would be torn between Python and Rust.

The case for Python is that I'm already very experienced in it (nearly 20 years), there's a good job market out there for it, and the ecosystem is one of the best in existence. It's like a comfortable well made jacket, maybe a tad worn in some areas but very functional. And it's not standing still, with a community that's committed to constant improvement.

Rust is more fun. I like the way it's been put together. It can also be used in more areas. There are some niches (wasm, low level, kernel) where Python just doesn't work. It has been able to benefit from the years of mistakes from Python and other languages on things like how it handles Unicode strings. I don't know it as well as Python, but I barely get a chance to work with it so that could change quickly in time.

Clojure, can't stop using it, so fun to use!

Rust, hands down.

Ruby. It’s designed for developer happiness, and it’s beautiful. Not as beautiful as it once was, but still lovely to code in.

JavaScript. I can't think of anything else that can be used for everything. It's a back-end language, a front-end language, it can be used for styling and animation, it can be an OOP language or a scripting language, and can make database queries & submissions. Is there another language that is as versatile for website development? I can't think of one.

Go. Nothing strikes a balance of ease and performance like go

Zig

Choosing a high-level language would limit your world so all of those are out. I could make my own high-level language if absolutely necessary from Zig but the reverse is not possible.

Zig > C as it's easier to write safer more secure code while being as fast or even faster than C, and usable in embedded and other places only C is normally used. In fact, I can create C binaries with my Zig compiler.

Zig > Rust because actually writing safe Rust code would use all my time and sanity so would end up writing unsafe Rust, but then what's the point.

Zig > Go because Go is slower, higher level, and backed by one of the most evil entities to ever exist.

DNA

Definitely lolcode.. HAI Can Has stdio KTHXBYE :)

Go or Rust

Clojure. Simple language for complex things. It also has java interop and Javascript interop and c# interop. So I will be fine.

I'm surprised no one has picked either macro assembly on their favorite ISA or, perhaps just to screw with people, Forth.

JavaScript

C. I've been programming for over 30 years and it's the only language to survive. Imagine if I was asked this question 30 years ago and picked perl or Pascal, I'd be screwed today.

JavaScript because you can do everything with it and long term all other languages will, most likely, gradually fade away (except for C/C++).

Big Kotlin fan.

Similar reasons to the commenter that talked about using a world class runtime, but the JVM is tested and works.

And now I can use Kotlin to make cross platform applications, while still utilizing the Java knowledge that I unfortunately possess? Perfect!