To crocodile, or krokodili, means to speak one’s native language at a gathering of Esperantists, a practice generally frowned on by Esperantists, according to an article I found today.
The article gives an interesting account of the history of Esperanto and the life of it’s inventor, Ludwig Lazarus Zamenhof. For a while Zamenhof apparently considered trying to make Hebrew and/or Yiddish into international languages, but later changed his mind as he considered a revival of Hebrew futile. He also urged Yiddish speakers to adopt the Cyrillic alphabet.
The article also mentions two other interesting Esperanto words: aligatori (to alligator), which means to speak one’s native language with someone speaking it as a second language, and kajmani (to cayman), which means to converse in a language that’s native to neither speaker.