I wish I could speak Finnish. But, actually, there are tons of languages I wish I could speak. All of them, really, but Finnish is the first one I thought of just now.
I’m in the US and English is my my primary language. I studied Russian but have forgotten a lot of it. I know a few words of German and French, but very few.
Edited to add: Please tell me what your primary language is. It would also be interesting to know what other languages you speak, if any, and where you currently live.
I minored in Japanese as an undergraduate. I kept studying it during grad school, where I got both a Masters and PhD in Linguistics.
I still really wish I could read Japanese. Conversationally I’m OK. But literacy as a non-native takes extra commitment.