English has become an international language, with a large number of governments promoting its study for national prosperity and economic development. However, there have been only a few empirical studies concerning the impact of English proficiency on the economic development of nations. These studies utilized some economic development indicators such as GDP, GDP per capita, as well as GDI. They also adopted various English proficiency indicators: average TOEFL scores, average EF Standard English Test scores, and a comparison of the Outer Circle and the Expanding Circle. They focused on the influence of English proficiency on economic development and foreign trade, but not on prosperity. Results in this field significantly change depending on the types of indicators; therefore, further research is necessary with various indicators to draw a more complete picture. This study adopted the Legatum Prosperity Index as a prosperity measurement and compared the Expanding Circle and the Outer Circle with a t-test. The result showed that the former was superior to the later. The study further investigated the situation in Asia and Africa, since these regions have a significant number of Outer-Circle countries. The research outcome indicated that there was no significant statistical difference between two circles in these regions. These results suggest that having a large number of those who have high English proficiency does not always lead nations to prosperity. Furthermore, they imply that both educational policy makers and practitioners need to be aware that there are factors other than English which could lead a nation to prosperity. Future research could also be warranted: It is interesting to analyze the difference between the two circles by paying attention to each category of the Legatum Prosperity Index. Another avenue is to conduct the same research with newer data.
Prosperity, English Proficiency, Outer Circle, Expanding Circle