SUMMARY
This paper aims to quantitatively analyze the features of twelve Japanese historical fifth-year English-as-a-Foreign-Language (EFL) textbooks (Book-5) and their current counterpart by using correspondence analysis, and to compare the results with those of the correspondence analyses of the first- and third-year EFL textbooks (Book-1 and Book-3). The following were the obtained results. First, the correspondence analysis results proved capable of differentiating quantitatively the features of the textbooks dealt with. Second, the explaining categories were explained 84.4 percent by four dimensions: speech-oriented (+) vs. exposition-oriented (-) discourse (Dim 1), easy (+) vs. difficult (-) texts (Dim 2), variety-rich (+) vs. variety-poor (-) (Dim 3), and teacher-assistance (+) vs. non-teacher-assistance (Dim 4). Third, the similarities/differences of the thirteen Book-5 textbooks were explained by the categories similar to but slightly different from the Book-1 and Book-3 results up to the fourth dimension. Finally, the results of the present correspondence analysis were graphically represented by (1) two-dimensional coordinate representation covering only Dim 1 and Dim 2 and (2) cluster-analysis-based dendrogram covering all the features of twelve dimensions specified. On the former, only Sunshine-5 and Seisoku-5 were distinctively different from the other textbooks, which proved the correspondence analysis map comprised of Dim 1 and Dim 2 to contribute to differentiating their inter-relationships, while on the latter, the same two textbooks were also distinctively different from the others. This could suggest the two textbooks should be closely examined from the qualitative perspective as well as the quantitative one.https://doi.org/10.26803/ijlter.18.12.6