3 things.

I would always be very wary about singing a song in a language I didn't know fairly well. I even have trouble with American sometimes, and it's very similar to English most of the time.

I would also be wary about using someone else's decoration - that way lies the peril of trying to sound like Bert Lloyd or Peter Bellamy, but sometimes it is hard to distinguish variation of the tune from decoration.

Once upon a time we were trying to recruit a fiddle player. He ran a construction company. He used to practice the violin on the M25 - mostly in traffic jams but he claimed he could steer with his knees. Now that's harder than learning lyrics in the car.