Thanks 'nl, 'nostrademons and 'rcpt for the links! I've been using Chronicity[0] in my project, and I hand-hacked a Polish-to-English regexp "translator" to make it work with Polish language[1]. I'll be looking at the sources of the libraries you provided as well as papers they reference; maybe I'll manage to steal some code :).
[0] - https://github.com/chaitanyagupta/chronicity
[1] - it's surprising how easy is to get 80% there with hacks like these: https://github.com/TeMPOraL/alice/blob/master/language.lisp#...