A very old joke that may have been posted on here some time ago.
Yankel was walking down a main street in Chinatown when he passed a small store called Yossele Rosenbergs dry cleaners. Curious about the name he walked in and asked to see the owner. An older Chinese walks out and asks him what he can help him with.
Yankel: tell me something, how did you end up with a name like Yossele Rosenberg?
Yossele: in Ellis island, all those years ago, I somehow got on a line with people from Europe. When it was time for the guy ahead of me to go, they asked him what his name was so he answered Yossele Rosenberg. Then they asked me, and I told them Sem Ting.
another joke, somewhat related:
Ellis Island was jammed with immigrants. One man stood in line, saying something to himself over and over. When he was asked his name, even though he repeated it many times, he forgot it.
guard: Sir, what’s your name?
man: oy, ich shoyn fargesen (I forgot)
guard: Sean Ferguson, welcome to the US