phrase used after someone says something to you, but you have no idea what the hell he/she is talking about.
person: dude! did you know that mathematicians have discovered that the convergence of a sequence also means that for every epsilon greater than zero, there exists an number "N" such that if "n" is greater than "N" then the absolute value of the limit subtracted by the term is less than epsilon?
you: **short pause**
you: i don't speak japanese