A special parser for learning English composition - Error analysis & learners´ model for ILTS

By embedding the function of automatically correcting nearly free format English translations of given Japanese sentences, we have developed a new ILTS(intelligent language tutoring system) for improving English Writing Skills in a L2 tutoring environment. In addition to a diagnostic engine capable of identifying grammatical, lexical and word usage errors of students´ input translations and returning error contingent feedback, we have developed a simple table look-up parser for displying the grammar trees. The table look-up parser parses a user input, which is always erronous, by simply matching the extended part-of-speech tag sequence of a closing sentence in a template of ILTS to the entries of a look-up-table, in which each extended part-of-speech tag array corresponds to one grammar tree. The complexity of the table look-up parser is O(n), where n denotes the length of a sentence. This shows a marked improvement over the general purpose parser of which the complexity is O(n³).