Natural Language Processing (NLP) is one of the most important research and application area in artificial intelligence. Here, with improvement of technology, humans and machine interaction is now possible as one of the important application areas in NLP. The basic tool of human - machine interaction is the language. Then, it is obvious that how important is the ability of understanding and interpreting of natural language by computer. For this interaction, expressions in natural language must be converted to a form that understandable by the machines. In this study, a dialog-based system, under the Turkish grammar rules, is designed so that computers are able to understand and interpret the text from dialogues.