2006, Patrick Blackburn · Johan Bos · Kristina Striegnitz,Learn Prolog Now!, §7.1
Prolog has been used for many purposes, but its inventor, Alain Colmerauer, was interested incomputational linguistics, and this remains a classic application for the language. Moreover, Prolog offers a number of tools which make life easier for computational linguists, and we are now going to start learning about one of the most useful of these: definite clause grammars, or DCGs as they are usually called.
