Language Log was asked;

When an English speaker doesn’t understand a word one says, it’s “Greek to me”. When a Hebrew speaker encounters this difficulty, it “sounds like Chinese”. […] Has there been a study of this phrase phenomenon, relating different languages on some kind of Directed Graph?

To answer the query, Mark Liberman checks out Wikipedia’s ‘Greek to me’ entry (among other sources) and produces a rather elegant directed graph depicting what languages are stereotypically incomprehensible to others.

The accompanying discussion is also noteworthy. As one commenter points out, the fact that the resulting directed graph is acyclic implies a sort of ordering or hierarchy of language incomprehensibility.

via Kottke