The Forth situation is a little bit different: it is a language designed to be easily to implement, so everyone is redoing Forth all the time, including its own creator (Cf. Colorforth) who said that "Forth is what Forth programmers do" [1].

At the same time Forth has had an unofficial standard as soon as 1979 (Forth-79 followed by Forth-83) before the official ANSI standard (1994).

Actually, a splintered community is not an entirely bad sign. It means that there is no monopoly and that the sub-communities are wealthy enough that they don't need to make compromises with their siblings in order to survive.

[1] http://www.ultratechnology.com/moore4th.htm