User-guided system development in Interactive Spoken Language Education

This paper is a Case Study of user involvement in the requirements specification for project ISLE: Interactive Spoken Language Education. Developers of Spoken Language Dialogue Systems should involve users from the outset, particularly if the aim is to develop novel solutions for a generic target application area or market. As well as target end-users, SLDS developers should identify and consult "meta-level" domain experts with expertise in human-to-human dialogue in the target domain. In our case, English language teachers and publishers provided generic knowledge of learners' dialogue preferences; other applications have analogous domain language experts. These domain language experts can help to pin down a domain-specific sublanguage which ts the constraints of current speech recognition technology: linguistically-naive end-users may expect unconstrained conversational English, but in practice dialogue interactions have to be constrained in vocabulary and syntax. User consultation also highlighted a need to consider how to integrate speech input and output with other modes of interaction and processing; in our case the input speech signal is processed by speech recogniser, stress and mispronunciation detectors, and output responses are text and graphics as well as speech. This suggests a need to revisit the definition of "dialogue": other SLDS developers should also consider the merits of multimodality as an adjunct to pure spoken dialogue, particularly given that current systems are not capable of accurately handling unconstrained English.