This paper reports on a comparative analysis of new and old versions of English textbooks at the secondary educational level in Japan (New Horizon and Sunshine) and those at the primary educational level in China, Malaysia and Thailand (Book 3 to Book 5, used from the third year of English study). The motivation behind this work lies in the belief that these analyses shed important light on the classroom content of teaching English as a foreign language. This study focuses on a comparison of the frequency of the wh-interrogative questions taught in the abovementioned English textbooks. The aim is to analyze the corpora in order to identify some of the differences among the textbooks and to explore the findings which reflect the English language teaching curriculum in Japan. Each textbook was first digitized and then analyzed in terms of the wh-interrogatives. The results reveal the following:
First, the total number of words is greater in the new versions of English textbooks in Japan than in the old ones. However, Sunshine (new version) has a much larger total number of words than New Horizon (new version), and also, the wh-interrogatives in Sunshine, especially what and how, are more frequently encountered than in New Horizon.
Next, when comparing the new and old versions of the textbooks, it was found that New Horizon has improved only slightly in terms of wh-interrogatives. The reason for this can be attributed to higher frequencies of where, when, and how in the old version than those of the wh-interrogatives in Sunshine. On the other hand, the total frequencies of the wh-interrogatives, especially what and how, are higher in Sunshine, and in this respect it can be said that Sunshine has improved compared with the old version.
With regard to the use of wh-interrogatives, it is doubtful whether there is coherence between primary school and junior high school textbooks, because overall the occurrence of wh-interrogatives is limited in primary school textbooks. Regarding the what interrogative, however, it seems that various types of expressions are offered to primary school students and then what they learn is reviewed and further developed at junior high school. Even so, it cannot be denied that sufficient examples of wh-interrogatives in Japanese textbooks have not been offered to students even though the textbooks are an improvement on the old ones.
Finally, a comparison of the new versions of Japanese textbooks with other Asian countries’ English textbooks shows that regarding the total number of words and wh-interrogatives, English textbooks in Japan still need to be improved. However, from the viewpoint of the frequency of wh-interrogatives, both of the Japanese textbooks can be said to be getting closer to those of other Asian countries.