Abstract. In order to extend the application domain of natural language interfaces to more realistic tasks without the decrease of user’s performance, it is desirable for users to be able to specify their requests as coherent texts consisting of more than one sentence, in other words, to write a program in everyday language. In this paper, we present a processing model of a natural language interface that accepts such an input text. It consists of the text understanding process using a systemic functional linguistic resource called the Semiotic Base, and the mapping process from the structure of the input text to the structure of an output computer program. The algorithms explained in this paper have been fully implemented in our everyday language programming system that deals with personal email management tasks.