I just love using French cooking terms, they make things sound so much sexier and intricate. "Well I just ciseleed some onions and sauteed them in my sautoir" has a much greater air of intrigue than "I diced some onions and fried them in a skillet".
These terms do play a vital role in professional kitchens though. They act as a short cut language so that precise instructions can be communicated in a concise manner. My six month stint at the FCI has hard wired these terms in my head and I have to think to come up with the non-French term.
So, to impress your friends and neighbors at your next cook out, be sure to talk about the beautiful quadrillage you achieved on your steaks. They will ooh and ah and agree with you even though they have no idea what you mean. Quadrillage is the French term for cross-hatch grill marks. Bon Appetit!