Lisp and prolog are old languages that have had their day and largely been marginalized by more practical ones. Prolog was intended for AI and NLP but overtime the rigid grammar approaches have been obsoleted by statistical ones with far greater success. These days AI and NLP are more commonly found in java or python. Watson, for example, is written in java. Lisp is great for things like genetic algorithms because there's no distinction between code and data, it's a homoiconic language.