For people with serious disability, it is most significant to be able to use the same communication methods, for instance a telephone and an electronic mail system (e-mail), as ordinary people do in order to get a normal life and communicate with other people for leading a social life. In particular, having communications access to an e-mail is a very effective method of communication that enables them to convey their intention to other people directly while at the same time keep their privacy. However, it takes them much time and effort to input an e-mail text on the computer. They also need much support by their attendants. From this point of view, we propose a multi-modal communication system that is composed of a voice recognizer, a pointing device, and a text composer. This system intend to improve the man-machine interface for people with physical disability. In this system, our voice recognition technology plays a key role in providing a good interface between disabled people and the personal computer. When generating e-mail contents, users access the database containing user keywords, and the guidance menu from which they select the appropriate word by voice. Our experimental results suggest that this communication system improves not only the time efficiency of text composition but also the readiness of disabled people to communicate with other people. In addition, our disabled subject on this paper is not able to move his body, legs and hands due to suffer from muscular dystrophy. And he is able to move only his fingers and speak command words with the assistance of a respirator.

We propose a new definition of the k-tail for a tree with respect to a tree set and show how it can be used to infer a frontier-to-root tree automaton from a finite set of trees. The behavior of the inference algorithm for varying values of k is also studied.

An error-correcting parsing method for context-sensitive languages is described, which finds all sentences ω's in a language with the minimum weighted Levenshtein distance WLD (ω, T) for input string T. The method is obtained by adding an error-correction mechanism to the Adachi-Kamata's parsing method for context-sensitive languages. By introducing the notion of a WLD-graph we can split the error-correction mechanism from the derivation of sentence i.e., the construction of derivation graphs. This makes the algorithm conceptually simple and easy to understand.

A loop detection is inherent in a context-sensitive parsing. A new detection method is presented for a top-down context-sensitive parsing using a grammar GE. This method requires only two input items, while the previous one requires three.