Natural language user interface

The natural language interface is an important component in intelligent computer assisted instruction (ICAI). The paper describes in detail the design method and implementation techniques of a heuristic natural language interface in an ICAI system which is oriented to a chemistry course for students in middle school (the system is named CCICAI). The design method and implementation techniques integrate properly the natural language and speech processing techniques and also the characteristics of heuristic teaching. The natural language interface of the CCICAI system not only increases the flexibility and adaptability of human computer interaction, but also enhances the functions of the system