Zen is implemented in Pidgin ML, which is a core subset of the Objective Caml programming language under the so-called revised syntax.
The Zen toolkit has been abstracted from a computational linguistics library for Sanskrit under development. Its application to the analysis of Sanskrit euphony (sandhi) is available as an article in PS and PDF format.
This toolkit has been applied by Sylvain Pogodalla and Nicolas Barth to the morphological analysis of French verbs (300 000 inflected forms for 6500 verbs); visit the LiToTe linguistic resources site.
A documentation is available in literate programming slide as a pdf document. A compressed tar file is available. Under Unix/Linux/MacOSX, untarring this file will produce a directory ZEN_2.1, in which the README file will provide installation information. Enjoy!
This library, with copyright INRIA, is distributed as free software under the LGPL license.
If you want to be informed of further developments, write me to be included in the Zen distribution list.