67 , 2016-03-31 , 琉球大学法文学部国際言語文化学科（欧米系） , Department of Languages and Cultures Euro-American Studies Faculty of Law and Letters University of the Ryukyus
Japanese learners of English have been repeatedly reported to be unable to distinguish English /R/―/L (e.g., Miyawaki, Strange, Verbrugge, Liberman, Jenkins, and Fujimura, 1975). With "communicative competence" being a central focus of English education goals, language teachers may regard this phenomenon as a small issue like a matter of minimal-pair discrimination. Yet from a viewpoint of categorical perception ― which is fundamental to building proficient listening ability both in L1 and L2 ― development of such discriminatory ability should not be neglected. With this in mind, another way to look at the difficulty that Japanese learners generally have with /R/―/L/ sounds is that the issue can be attributed to their difficulties attending to the F3 component of English sounds acoustically. A series of experiments conducted at ATR International (e.g., Callan, Tajima, Callan, Kubo, Masaki, & Akahane-Yamada, 2003) investigated this notion by offering acoustic training to Japanese learners for difficult phonemes such as /R/-/L/ and this paper continues this line of inquiry. Other streams of research have used various methods, approaches, and learning materials to assert that, whereas Japanese listeners are accustomed to frequencies closer to the 1500Hz range (Tomatis, 1993), they need to be taught how to tune in to frequencies that are closer to the English language passband at around the 2000Hz range and above. This paper reports four examples of commercially available methods that incorporate the above notion, namely (1) the Thomatis Method, (2) the Denda Method (Listening Dr.), (3) Biolistening by Akamatsu, and (4) Miracle Sounds 8000Hz English Listening Therapy by Shinohara. The paper compares and discusses how each method described the "high frequency effects" in relation to expected learning results.