Here in Botswana, we have a Chinese corner for students to improve their speaking skills. These learners are very passionate about the language, because many plan to do business in China," Pu said.

Yet Botswana does not sparkle as brightly as it used to. The price of natural diamonds, which make up more than 80% of exports, has slumped by about 30% over the past three years.

Learning a language — as an adult, at least — takes work. Language learning apps can help motivate you to do that work. Most of them are designed for you to use them for just a few minutes a ...