Tense Generation in an Intelligent Tutor for Foreign Language Teaching: Some Issues in the Design of the Verb Expert

TENSE GENERATION IN AN INTELLIGENT TUTOR FOR FOREIGN LANGUAGE TEACHING: SOME ISSUES IN THE DESIGN OF THE VERB EXPERT Danilo FUM (*), Paolo Giangrandi(°), Carlo Tasso (o) (*) Dipartimento dell~ducazione, Universita' di Trieste, Italy (o) Laboratorio di Intelligenza Artificiale, Universita' di Udine, Italy via Zanon, 6 - 33100 UDINE, Italy e.mail: tasso%uduniv.infn.it@icineca2.bitnet ABSTRACT The paper presents some of the results obtained within a research project aimed at developing ET (English Tutor), an intelligent tutoring system which supports Italian students in learning the English verbs. We concentrate on one of the most important modules of the system, the domain (i.e. verb) expert which is devoted to generate, in a cog- nitively transparent way, the right tense for the verb(s) appearing in the exercises presented to the student. An example which highlights the main capabilities of the verb expert is provided. A prototype version of ET has been fully implemented. 1. INTRODUCTION In the course of its evolution, English has lost most of the complexities which still characterize other Indo-European languages. Modern English, for example, has no declensions, it makes minimum use of the subjunctive mood and adopts 'natural' gender instead of the grammatical one. The language, on the other hand, has become more precise in other ways: cases have thus been replaced by prepositions and fixed word order while subtle meaning distinctions can be conveyed through a highly sophisticated use of tense expressions. Learning correct verb usage is however extremely difficult for non native speakers and causes troubles to people who study English as a foreign language. In order to overcome the difficulties which can be found in this and several other grammatical areas, various attempts have been made to utilize Artificial Intelligence techniques for developing very sophisticated systems, called Intelligent Tutoring Systems, in the specific domain of foreign language teaching (Barchan, Woodmansee, and Yazdani, 1985; Cunningham, Iberall, and Woolf, 1986; Schuster and Finin, 1986; Weischedel, Voge, and James, 1978; Zoch, Sabah, and Alviset, 1986). An Intelligent Tutoring System (ITS, for short) is a program capable of providing students with tutorial guidance in a given subject (Lawler and Yazdani, 1987; Sleeman and Brown, 1982; Wenger, 1987). A full- fledged ITS: (a) has specific domain expertise; (b) is capable of modeling the student knowledge in order to discover the reason(s) of his mistakes, and (c) is able to make teaching more effective by applying different tutorial strategies. ITS technology seems particularly promising in fields, like language teaching, where a solid core of facts is actually surrounded by a more nebulous area in which subtle discriminations, personal points of view, and pragmatic factors are involved (Close, 1981). In this paper we present some of the results obtained within a research project aimed at developing ET (English Tutor), an ITS which helps Italian students to learn the English verb system. An overall description of ET, of its structure and mode of operation has been given elsewhere (Fum, Giangrandi, and Tasso, 1988). We concentrate here on one of the most important modules of the system, …

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