If you learn French, you will already be able to read and understand some bits of Spanish and can learn it without a ton of effort. A bit harder the other way around.

Never too late to start. If you already know English and some German, Dutch should be even easier than it already is.

I see your pedantry and raise you my own:

There are absolutely languages nobody speaks in your region even if you live in a city.

I therefore choose sign language or Assembly.

Ithkuil! For the sheer information density and the bragging rights of being fluent in a language not even its creator can speak

Spanish helps learning French more than it helps reading French, from experience

Heh, I guess I wouldn't say I "speak" it, but between programming games and actual coding, I think I've used 4 or 5 different dialects of assembly.

latin. old english

Probably one of the nordic languages as everyone from my country is going there for work.

Its OK, I'm European and couldn't distinguish a Swede from a Fin.

Malay probably

Would probably go for Japanese since I watch too much anime and Japanese media so learning Japanese would be super useful.

But then most anime and tons of Japanese media is translated anyway, except for music, but in that case I listen to a lot more of German music than I do Japanese, so maybe I would learn German instead.

But then, I can probably learn German much easier the traditional way that I can an Asian language, so maybe I should use the cheat to learn the language that would be harder for me to learn traditionally than just German. (Even though I've watched so much anime by now that I effectively can understand Japanese much better than I do German.)

Cobol.

EESTI RIIGI KEEL, ON EESTI KEEL!!!!

anyways i choose cornish so i can continue learning German and after that Spanish.

Haven't picked back up consistently learning Japanese in like 8 years, but it's a joy to feel the progress of learning such a vastly different language. I know enough Spanish that it'd be a waste to spend this gift on it.

I guess the most tactical option for me that's still interesting would be Arabic, because while I love the idea of knowing it, I don't think I'll ever give myself the time to learn it.