Dix-neuf
Dix-neuf is the word for nineteen (19) in the French language. Unfortunately, it rhymes with "Deez Nuts," a popular joke from vine, which can be misinterpreted. This number is also the mathematical answer to 9+10, another fad from vine.
If you're practicing mathematics with someone who can speak French, be wary of anyone who uses vine. They may confuse dix-neuf with deez nuts.