@kev Another vote for #javascript. It's gotten much better in the past few years; many (not all) of the issues people have with it have now been fixed. And, after all the work browser vendors have put into optimizing its interpreter, it's *really* fast (for an interpretated language, I mean).
It's also very flexible in terms of paradigm: it supports functional programming or #OOP pretty well.
Plus, it's a C-family language, so it would make it easier to learn C/C++/Rust/go/etc. one day.