Why should you learn any language other than Java?

I’ve always been interested on that theory stating that it was language, as a tool, what ultimately lead to the out-of-nature-ranges development in the way human-beings’ mental process works.
Until yesterday, I didn’t know that this is called the Sapir-Whorf Hypothesis.

I’m wandering, sorry. Yesterday I came across a Ruby presentation: “ 10 Things Every Java Programmer Should Know About Ruby ” by Jim Weirich. I liked it very much but , best of all, I greatly enjoyed one of the opening quotes:

Quote

A language that doesn’t affect the way you think about programming is not worth knowing – Alan Perlis