"Hey, can't you tell my voice from a ten-year-old? Ay caramba!"
The 10 year old voiced man is a man who sounds a lot like Bart Simpson.
He was a construction foreman in Springfield. After the student body was out of school due to a massive teacher's strike, Bart visited a construction lot and played his usual mischief, this time by using a megaphone and telling a crane operator to spin the crane real fast (which he did and was implied to have broken the crane due to velocity), as well as telling a sand dumper to dump three tons of sand onto the porta-potty. The Foreman busts Bart and snatches away the megaphone from him, just to angrily ask how they could mistake his voice for a ten-year-old kid's voice, and exasperatedly says to himself, "Ay Caramba."