Hendrix, G. G. (1977). The LIFER manual: A guide to building practical natural language interfaces. Stanford Research Inst..
This document describes an application-oriented system for creating natural language interfaces between existing computer programs (such as data base management systems) and casual users. The system is easy to use and flexible, offering a range of capabilities that support both simple and complex interfaces. This range of capabilities allows beginning interface builders to rapidly define worktable sublets of English and gives more advanced language definitions. The system includes an automatic mechanism for handling certain classes of elliptical (incomplete) inputs, a spelling corrector, a grammar editor, and a mechanism that allows even novices, through the use of paraphrase, to extend the language recognized by the system. Experience with the system has shown that for many applications, very practicable interfaces may be created in a few days.