if one could choose a course that would result to be the ideal learning experience to that individual, what would it be? one might say an Anatomy or Physiology.

This paper discusses linguistic issues that one must address in order to design an e ective CALL system for second language learners. We focus on how one should develop an error taxonomy and indicate how that taxonomy can a ect the design of the entire system. This work was done in the context of designing a CALL tool to help native signers of American Sign Language (ASL) learn written English. Here we report the methodology used in developing the error taxonomy for the system. Our analysis of writing samples from ASL natives indicates that language transfer (LT) (when considered appropriately) can account for many of the errors we found. Recognizing this possibility has substantially in uenced the error taxonomywehavedeveloped. The resulting taxonomy captures the true source of many errors and will allow the eventual system to take advantage of ASL knowledge when teaching English. We provide a characterization of language transfer that provides a broad perspective on the ways that two languages may di er and indicates how these di erences could potentially in uence acquisition and production of the second language. In addition, we argue that an e ective CALL system must not only examine sentences in isolation, but it must identify and correct discourse-level errors. We point out that the source of several error classes we identi ed rests in discourse-level processing. We showhow these errors can

In this paper we introduce a computerassisted writing tool for deaf users of American Sign Language (ASL). The novel aspect of this system (under development) is that it views the task faced by these writers as one of second language acquisition. We indicate how this affects the system design and the system's correction and explanation strategies, and present our methodology for modeling the second language ac- quisition process.

Correcting text which is ill-formed with respect to grammar and/or discourse strategies is a challenging problem. We are working on this problem from the perspective of helping deaf writers produce text which conforms to the standard rules of English. 2 This perspective mayprove tobe particularly interesting since the native language of some deaf writers is American Sign Language

In this paper we discuss an envisioned text planner for a computer-assisted instruction tool for deaf learners of English. We describe the problem of deaf literacy and overview our system, designed to act as a writing tutor that generates text to explain the errors found in a user's written compositions. These explanations are created according to a response anatomy that divides the planning task into a bottom-up phase for grouping and ordering explanations and a top-down phase for building a hierarchical text plan to create the explanatory text. This is then followed by a revision of the complete plan to place it in its greater context. At all levels of planning, the explanation is personalized to the individual learner's styles and knowledge in order to maximize the learning experience. Introduction The problem of deaf literacy has been well-documented and has far reaching effects on every aspect of deaf students ' education. Although data on writing skills is difficult to obtain, ...

In this paper we discuss how generation issues affect the design of a computer-assisted language leaming tool designed to teach written English as a second language to deaf users of American Sign Language. We discuss a dual-component linguistic model that attempts to reflect the generation process of the leamers. The first model component captures the influence of the first language on the acquisition of the second. The second model component captures the process of second language acquisition itself. The linguistic