Well, I'd like to "speak" the two that I've tried to learn well enough to get near fluency first. Spanish is kinda meh from me, I sound like a five year old at best. My signing (hence the "" around speak) is maybe a tiny fraction better, by vocabulary, but my arthritis has killed my ability to use it.

English is my first language, American version, southern dialect (if you consider it distinct enough to merit that term).

If my brain could pick up languages easier, I would pick up gaelic/erse first. One side of my family is heavily irish, and I love the sound of it.

After that, I'd go for Japanese because I love the sound of it and I'd love to be able to watch my favorite Kurosawa films without subtitles or dubbing.

Back over to Europe for German because the other side of my family runs heavy to German ancestors.

I have a list in my head of this general question tbh. It goes on a while.

But, realistically, without a magic wand, it won't happen. I took years of spanish in high school and college, dated a Mexican girl during part of high school, then a very lovely lady from Columbia later on. So I had access to native speakers over time, but never could really "click" into fluency. Since then I've lost a bunch of the grammar and vocabulary I used to have. The chances of me actually learning any other language now approaches zero since I don't have the advantages I had then.

I've always envied folks that pick up languages relatively easy