The government’s decision to make the study of English mandatory for fifth- and sixth-graders in Japan beginning in 2020 is a step in the right direction. But its success in preparing young people for the world that awaits them largely depends on the skill of the teachers public schools hire.

That’s why the outlook is not encouraging. According to an education ministry survey in fiscal 2015, only 4.9 percent of elementary school teachers were licensed to teach English. Despite efforts by the government beginning in fiscal 2014 to increase the number of expert teachers, there still remains a huge shortfall.

The challenge, however, is not only to recruit 144,000 new English teachers, which alone is daunting enough, but to hire those who possess the expertise to boost the ranking of Japanese students on the TOEFL (Test of English as a Foreign Language). Japan stands at the bottom of the list on the speaking ability of its students. Improving that humiliating distinction will require finding native English speakers.

That’s because English, like many languages, has various dialects. As a result, if Japan wants students to learn how to speak the kind of English spoken in the United States, it behooves the government to recruit teachers who were born and schooled there. For example, there is a difference between the pronunciation and accent of a teacher from India and that of a teacher from America. Both speak English, but they often have trouble understanding each other.

By the same token, there are differences between the Spanish spoken in Spain from that spoken in South America. It’s not just a case of idioms but also of pronunciation. Since so much of learning any language is directly dependent on what is heard on a daily basis, great care needs to be taken to provide Japanese children with the desired model.

The problem for Japan is compounded by the scarcity of such speakers who also have the personality to interact with elementary school children. Graduation from a marquee-name university is no assurance of success in the classroom. Much depends on individual style. When differences in culture are factored in, the task becomes even more daunting.

For example, native English speakers from the United States are unfamiliar with the concept of mimamoru, which is a unique Japanese pedagogical approach to observing and caring with minimal intervention. They are equally unaware of the concept of omoiyari, which stresses empathy and consideration for others. These and other vital cultural factors illustrate how Asians and Westerners think differently. Yet incorporating these concepts in instruction can make the difference between success and failure.

A similar situation exists when Japanese teachers are hired by schools in the U.S. They are shocked by the outspokenness of American children compared with their Japanese counterparts. They quickly learn to adjust their lessons to allow for more active responses. It’s not a matter of lack of subject matter expertise but instead of unfamiliarity with cultural differences.

That old saw about England and the United States perhaps best summarizes the issue facing Japan: two countries separated by a common language. The more that non-Japanese become immersed in Japanese culture and how Japanese elementary school teachers act and talk, the more likely their prospects for success. Too much is on the line in the globalization of the economy to settle for anything less.

Walt Gardner writes the Reality Check blog for Education Week in the U.S.