Pronunciation Portfolio —How were, are, and will be you? —

No two students are the same. There are about 2 billion students of English on this planet and each student is always evolving through training. This means that there are about 2 billion types of English pronunciation. Despite the tremendous number of pronunciations, there has been no good method so far to represent each pronunciation individually. This study intro-duces a very novel method to represent the individual pronunciations. The method is based on physical implementation of structural phonology and the implementation can be regarded as a mathematical interpretation of Saussure’s claim that language is a system of conceptual differences and phonic differences. Each student’s pronunciation is acoustically and entirely represented as phonological structure with no dimensions to indicate non-linguistic features like age, gender, speaker, microphone, room, line, etc. This paper examines whether the struc-tural representation can provide a good tool for pronunciation assessment. Results of experi-ments with good and intentionally-bad pronunciations of a single speaker showed that all the students used in the experiment are acoustically located between the two pronunciations, in-dicating that the students are judged to be acoustically closer to the speaker than the speaker himself is. This result shows that the proposed method can delete the irrelevant factors effec-tively and is extremely reliable in CALL