nebulous

French would probably be the most useful (and "easiest" to learn if you know English already), though all of those sound pretty good.

if you want the easiest, french- i spent 3 years with only moderate effort and studying to learn how to speak semi-fluently and write with a bit of competence

if you want the most interesting, it'd be german or russian, though those are more difficult and might not be as useful

German was the easiest for me to learn as person who’s terrible at languages

WIR KAUFEN ALLE BEI ALDI

Apparently german is easier if you are fluent in english, if not french is the easiest. OR if you wanna insult the hackers learn russian

real talk though i'm sure youve already considered it but if you're doing a lot of cold war era stuff it might be cool to be able to read russian documents and sift through soviet historical material

Suka blyat idi nahui davai pidoras