In brief: common words tend to be short.

There is much more that can be said, including turning it around and finding the short words you use and assuming initially that they correspond to common or useful concepts. We actively use this in our design phase, giving longer names to new ideas, and gradually shortening them as it gets more tedious to use the better, and therefore more frequently referenced, concepts.

See also:
* TaskSchedulingUsingZipfsLaw ''(wherein several of the criticisms seem to miss why this is relevant)''.
* PowerLaw
* http://en.wikipedia.org/wiki/Zipf%27s_law
* http://planetmath.org/encyclopedia/ZipfsLaw.html
----
CategoryMath