argot

We borrowed argot from French in the mid-1800s, although our language already had several words covering its meaning. There was jargon, which harks back to Anglo-French by way of Middle English (where it meant "twittering of birds"); it had been used for specialized (and often obscure or pretentious) vocabulary since the 1600s. There was also lingo, which had been around for almost a hundred years, and which is connected to the Latin word lingua ("language"). English novelist and lawyer Henry Fielding used it of "court gibberish" - what we tend to call legalese. In fact, the suffixal ending -ese is a newer means of indicating arcane vocabulary. One of its very first applications at the turn of the 20th century was for "American 'golfese.'"