Why computational grammarians can be skeptical about existing linguistic theories

The bottle neck in building a practical natural language processing system is not those problems which have been often discussed in research papers, but in ilandling much more dirty, exceptional (for theoreticians, but we frequently encounter) expressions. This panel will focus on the problem which has been rarely written but has been argued informally among researchers who have tried to build a practical natural language processing system at least once. Theory is important and valuable for the explanation and understanding, but is essentially the first order approximation of a target object. As for language~ current theories are Just for the basic part of the language structure. Real language usage is quite different from the basic language structure and a supposed mechanism of interpretation. Natural language processing system must cover real language usage as much as possible. The system model must be designed in such a way that it is clearly understandable by the support of a powerful linguistic theory, and still can accept varieties of exceptional linguistic phenomena which the theory is difficult to treat. How we can design such a system is a major problem in natural language processing, especially for machine translation between the languages of different linguistic families. We have to be concerned with both linguistic and non-llngulstlc world. While we have to study these difficult problems, we must not forget about the realizability of a useful system from the standpoint of engineering. I received valuable comments from Dr. Karen Jensen who cannot participate in our panel, and kindly offered me to use her comments freely in our panel. I want to cite her comments in the followings.