I've found a non-English answer to this question. My initial reaction was to comment, asking for translation, and then flag for moderation (regardless of language, it looked poor).
But I couldn't really find any reference in the help-center, that would specifically state that questions and answers should be in English. There are points about grammar and punctuation, but not explicitly language.
So, if Travel SE is English-only, what is the best way to handle non-English questions and answers, so that new users do not feel disrespected?