In this study we attempted to illustrate to what extent Japanese university students who study English immediately after their enrolment have acquired English short vowels using graphs and a three-dimensional (= 3D) vowel chart, and thus to clarify what their problems are while simultaneously producing American English short vowels. There was a prediction that Japanese learners of English (JEL2) have weakness in lip-rounding and protrusion since there are no such articulatory movements in Japanese vowels. This was clarified while observing F2 and F3. JEL2 have problems with simultaneous in lip movements, the jaw movements in general in this case. Also we found that there was a difference between female and male JEL2. As far as this experiment is concerned, female JEL2's tongue and jaw movement (F2) is less stable than males'. Moreover, it may be confirmed that the 3D Vowel Chart may be more useful for EL2 than the graph.
Bibliographic reference. Isei-Jaakkola, Toshiko / Naka, Takatoshi / Hirose, Keikichi (2011): "Problems encountered by Japanese EL2 with English short vowels as illustrated on a 3d vowel chart", In INTERSPEECH-2011, 1625-1628.