English is my second language and Latin my third. While the latter is not as useful as learning Spanish or French in day to day communication, it really helped my English capabilities as a lot of words in English are Latin based.

My favorite etymological thing is the German „Bank“ which can mean bench or bank. Funnily enough the financial institution is a loan via the Italian „banca“ but that itself goes back to the same old Germanic root as the bench you sit on.