Uninterrupted interactions of merchants and travelers from different countries stress the significance of English. The purpose of the study was to investigate what cultures and teaching practices are different between native English-speaking teachers and Taiwanese senior high school students. Three native English-speaking teachers and six Taiwanese senior high school students in Taichung city participated in this study. Data were collected through native English-speaking teachers' and Taiwanese senior high school students' interviews and non-participant classroom observation. Results showed that American teachers lack of diversified cultures, not dealing with the complicated classroom situations. Students were accustomed to Grammar Translation Method "GTM" instead of the Communicative Language Teaching "CLT." Scarcity of understanding diversified cultures and large classes were major difficulties for both teachers and students. The implications of the study were discussed and some recommendations were made to assist local English teachers and senior high school students in addressing their teaching or learning English.