He is laughing because he knows we'll never get to see a sign like this in an American hospital!

Ok- ok I will explain... Look over the lads right shoulder. See the broken concrete and the 'water' in the drainage ditch? This is in one of the courtyards of the hospital and the sign "Tanpri, pa pipi la" is on that post next to the water. The sign says, "Please, don't pee here."