The LINGUIST List is dedicated to providing information on language and language analysis, and to providing the discipline of linguistics with the infrastructure necessary to function in the digital world. LINGUIST is a free resource, run by linguistics students and faculty, and supported primarily by your donations. Please support LINGUIST List during the 2016 Fund Drive.
FYI: Free NLP and Prolog textbooks online
THE FOLLOWING TWO BOOKS, NOW OUT OF PRINT, HAVE JUST BEEN RELEASED, FREE OF CHARGE, AS PDF FILES ON THE WEB:
MICHAEL A. COVINGTON
NATURAL LANGUAGE PROCESSING FOR PROLOG PROGRAMMERS
MICHAEL A. COVINGTON, DONALD NUTE, AND ANDRE VELLINO
PROLOG PROGRAMMING IN DEPTH