Natural language processing comes in many varieties. The most robust natural language systems are tailored to the most limited applications. The simplest approach to natural language processing is to program the computer to look for a limited set of key words or phrases. When the computer finds these words it produces a programmed response. The ELIZA program offers a particularly compelling example of the keyword approach to natural language processing. ELIZA was written at MIT in the mid-1960s to mimic the role of a psychoanalyst interviewing a patient. Examples of ELIZA and related programs are now widely available on the web and personal computers.
ELIZA was never intended to be a model of natural language understanding, yet it is still one of the most popular artificial intelligence programs in the public domain. As long as the user accepts the premise that the program is conducting an open-ended interview, ELIZA can produce a convincing imitation of a talking computer. ELIZA works by searching for a list of keywords in the input. If the program finds one of these words, it asks a preprogrammed question that centers around the keyword. If the program does not find a word on its list, it chooses from a set of open-ended responses, such as Tell me more or Go on. Continue reading “Intro To Computational Linguistics”