The waiter

Benjamin and Morris are sitting in a wonderful Kosher restaurant in Hendon.
They are talking among themselves in Yiddish. A Chinese waiter comes up and
in fluent and impeccable Yiddish asks them if everything is okay, can he get
them anything, and so forth. Benjamin and Morris are dumbfounded.
"My God, where did he learn such perfect Yiddish?" they both think. After
they pay the bill they ask the manager, an old friend of theirs, also fluent
in Yiddish, "Where did your waiter learn such fabulous Yiddish?"
The owner looks around and leans over to them so no one will hear and says,
"Shhhh. He thinks we're teaching him English."