Well, the title says the most. Just searching for a new one to learn. Mine is in fact, Python 3.7. I like Python 3.7, because it runs on like everything, even on my small raspi zero.
Mh I should add that I, in this moment, I speak Python, R, in advanced 8/10 levels of skill, HTML in beginner level, as I do in CSS and C++. JS in mid levels of skill
Because it can be used for virtually anything. Server? Check. App? Check. Robot? Check.
Combined with html/JS/CSS, you can make a http server.