English Tag Questions (ETQs) are frequently used among native speakers in various situations. Though ETQs look simple and easy to learn, some ESL students with particular language backgrounds report that it is difficult to learn and utilize ETQs naturally. One of my hypotheses is that the familarity of ETQs depends on whether ELS students have similar syntactic structure in their native languages to English. To investigate this inquiry, I have compared syntactic structures of tag questions from five different languages: Polish, Deutsch, Chinese (Mandarin), Japanese, and Korean. In addition to the syntactic analysis, I have also surveyed Chinese, Japanese, and Korean ESL students, who comprise major population of ESL students, for their reflections on ETQs; whether they can differentiate the meaning of some basic syntaxes of ETQs. The results showed that there were significant differences in the responses of Chinese, Japanese, and Korean students: Chinese students are much better in general than Japanese or Korean students. This paper contends that ETQ is one of the idiosyncratic features of English, and suggests that the syntactic and pragmatic differences of various languages should be considered in order to teach ETQs effectively.