[Okay, we need a reference here as well - J is, in my understanding, a current version of APL like programming language - right?]
I have only used APL but I understand J is a newer version that removes the need for the APL font which was always a bane of any installation. Yet, it seems strange for this to happen in the days of Unicode and graphics displays. I don't think it makes it any easier to read though. See http://www.acm.org/sigapl/apl.htm
[There are many versions of J, the early versions are freely distributable in source, http://www.math.uwaterloo.ca/~ljdickey/#apl-j is a good resource. More recent versions are freely available only in binary form under a non-commercial license, http://www.jsoftware.com is the resource here. One thing which distinguishes J from other languages in the APL family is that Ken Iverson -- the guy who invented APL (to make it possible to document the IBM 360 architecture, back in the early 1960s) -- is also the architect behind J.]
[Also of possible interest is a writeup on A [L1 ] -- the implementation of A was important in getting J off the ground. This page is a bit hard to read, because it expects that you have a special font installed with implied special character mappings.]