Grand Canyon

One day, a retarded boy and his father decide to take a trip to
the Grand Canyon.

Upon their arival in the giant crack, the father yells out
“HELLOOO!” They hear the echo going “Helloo!” “hellooo”

The retarded boy is amazed at the echo, and tries yelling
something himself, “Yeref erad uauff kaschader!” The echo came
back, “What the fuck did you say?”