Learning clicking sounds is tough, especially online

In most parts of the world the clicks of Zulu and Xhosa, the languages spoken most commonly at home in South Africa, sound completely foreign. Duolingo, the world’s biggest language-learning platform, is hoping to make them more familiar. Next year it will offer lessons in both to its 40m active users.

https://www.economist.com/middle-east-and-africa/2021/10/28/a-language-teaching-app-tests-tongues-with-zulu-and-xhosa