Computational Linguistics

What is it?
Computational linguistics (CL) is a discipline between linguistics and computer science which is concerned with the computational aspects of the human language faculty. It belongs to the cognitive sciences and overlaps with the field of artificial intelligence (AI), a branch of computer science that is aiming at computational models of human cognition. There are two components of CL: applied and theoretical.

What is the "applied" aspect of CL?
The applied component of CL is more interested in the practical outcome of modeling human language use. The goal is to create software products that have some knowledge of human language.

Why is Applied CL needed?
Such products are urgently needed for improving human-machine interaction since the main obstacle in the interaction between human and computer is one of communication. Today's computers do not understand our language, and humans have difficulties understanding the computer's language, which does not correspond to the structure of human thought.

How is Applied CL useful?
Natural language interfaces enable the user to communicate with the computer in German, English or another human language. Some applications of such interfaces are database queries, information retrieval from texts and so-called expert systems. Current advances in recognition of spoken language improve the usability of many types of natural language systems. Communication with computers using spoken language will have a lasting impact upon the work environment, opening up completely new areas of application for information technology.

Although existing CL programs are far from achieving human ability, they have numerous possible applications. Even if the language the machine understands and its domain of discourse are very restricted, the use of human language can increase the acceptance of software and the productivity of its users.

What about communication between people?
Much older than communication problems between human beings and machines are those between people with different mother tongues. One of the original goals of applied computational linguistics was fully automatic translation between human languages. From bitter experience scientists have realized that they are far from achieving this. Nevertheless, computational linguists have created software systems, which can simplify the work of human translators and clearly improve their productivity.

What is the future of Applied CL?
The future of applied computational linguistics will be determined by the growing need for user-friendly software. Even though the successful simulation of human language competence is not to be expected in the near future, computational linguists have numerous immediate research goals involving the design, realization and maintenance of systems, which facilitate everyday work, such as grammar checkers for word processing programs.

What is the "theoretical" aspect of CL?
Theoretical CL takes up issues in formal theories. It deals with formal theories about the linguistic knowledge that a human needs for generating and understanding language. Today these theories have reached a degree of complexity that can only be managed by employing computers. Computational linguists develop formal models simulating aspects of the human language faculty and implement them as computer programs. These programs constitute the basis for the evaluation and further development of the theories.

What other branches of science are involved in Theoretical CL?
In addition to linguistic theories, findings from cognitive psychology play a major role in simulating linguistic competence. Within psychology, it is mainly the area of psycholinguistics that examines the cognitive processes constituting human language use. The special attraction of computational linguistics lies in the combination of methods and strategies from the humanities, natural and behavioral sciences, and engineering.