Alan Gordon writes:

"My second cousin, during an interview I conducted, informed me that his
grandfather, Frank Kanserstein, had his name changed at Ellis Island. 
Frank's was the husband of my great aunt, and I never met him. 
According to my cousin, Frank's real name was "Thomaspol," but when they
asked him what his name was, he replied, "Kanserstein," or "I can't
understand."  Given your combined experiences, does this make any sense?"

No, for several reasons.

1) Nobody would have asked him what his name was, because it would have
been written on his ticket and on the passenger list; the agent's job
was to match the two.

2) In what language would "Kanserstein" mean "I can't understand?" In
Yiddish it would be something like "kann nikht verstehen." This is an
old trope--I grew up hearing stories about people who went abroad and
got the name "Kannitverstahn." And supposedly the kangaroo got its name
from an incident where an explorer or other visitor asked what that
animal was, and was told, "I don't understand."
https://en.wikipedia.org/wiki/Kangaroo#Terminology debunks that story.
(And what language would it have been that was not spoken at Ellis
Island? Mr. KANSERSTEIN would have to have been in a small minority of
speakers of his language on that boat for there not to have been an
agent who could help.)

Roger Lustig

Princeton, NJ USA