R

R is a programming language designed for use in statistics. (Perhaps there are still a few letters of the alphabet as yet untaken for single-letter programming language names, but if not, there's always Unicode to be trawled for name-worthy characters.) It is an interpreted language, and the interpreter is distributed as free software. Built-in features include the ability to generate graphs and plots, as well as the ability to store an entire array (or "vector") in a variable and do mathematical operations on all elements of the vector with a single operator (similarly to APL). It can also do complex-number arithmetic (similarly to Python).

R is descended from S, so apparently they're going backward in the alphabet, unlike the transition from B to C.

Apparently the .R file extension is generally done in uppercase.

Links

 * Official site
 * Wikipedia article
 * R-Bloggers: R news and tutorials
 * An Introduction to R (free online book)