I've been skating on the barest surface of polyglotism for years, and am stunned at how basic some of the basics of other languages can be (if that makes any sense). Like, I didn't think they wouldn't be since kids have to learn them, just that I would have had a harder time picking it up.
As a kid, Hebrew and Hangul were enormously easy to get the alphabets down for, though I'm sadly out of practice. People are always calling Hiragana easy, though haven't tried (apparently there's a game for it on Steam). More recently, Cyrillic was an easy study, though I had a Russian friend on Steam helping me out on stuff. Shouldn't be too hard to get that back.
I was looking at the French language for like two weeks but never really followed through. Same with German. In face-to-face landlocked America, you pretty much have to go out of your way to find something that isn't English or Spanish. I think retention requires more than passing interest and the rush you get from native speakers gratified of your bumbling attempts.
To this date, I have never been mocked for a non-English error.