I wonder what the origin of "libertine" is? late 14c., "a freedman, an emancipated slave," from Latin libertinus "condition of a freedman; member of a class of freedmen," from libertus "one's freedmen, emancipated person," from liber "free"... 1570s, "free, unrestrained," originally in religion, from libertine (adj.). Meaning "licentious, dissolute" is from c. 1600. https://www.etymonline.com/word/libertine

When I was learning Russian, we were taught that a large portion of Russian is idiomatic and cannot be translated literally. For example, дождь идёт translates literally as "rain takes a walk," but really means "It is raining." This makes learning Russian even that much more difficult than English, not to mention the complex grammar in Russian with multiple declensions and cases for nouns and adjectives (even more than in Latin) and multiple ways of conjugating verbs, not counting all the irregular verbs. We were also taught that most Russians do not speak proper Russian - mainly because it is too difficult. English is much simpler and easier, and still native English speakers often do not speak proper English. It's too bad that Latin is not taught as much in schools as it used to be.

The European/colonial contact with Mexico was from Spain, on Brazil was from Portugal. Different countries, different languages. Real in Spanish means royal. Other countries have currency terms related to their royalty, mostly the crown as a monarchistic symbol. England used the term "crown" for specific coins at various times. In Scandinavian countries, it's the local form for crown - kroner, krona, krone. The Czech Republic still uses koruna.

Could be when the word was taken into English, we mispronounced it. Or maybe it was from a language other than German. Still sounds like an Old Country last name to me. eta: Okay I caved and looked it up. The origin probably came through the Old English, German, or Yiddish word for "chest", spellings (and opinions) vary.