1. The default file format a program uses to store data on disk. The format is often a proprietary file format. Many popular programs today can retrieve and save data in several formats. See ASCII. Computer scientists are working to improve computers so that they can respond to natural language. Human languages are so complex that no single model of a natural language grammar system has gashed widespread acceptance among linguists. The complexity OF human languages, coupled with the lack of under standing about what information is needed to decode human sentences, makes it difficult to devise programs that recognize speech. Progress in solving these problems has been slow. From QUECID