Vietnamese

Vietnamese is the most-spoken Austroasiatic language — 85 million native speakers concentrated in Vietnam, plus a global diaspora that gave the world Vietnamese food, the Saigon coffee renaissance, and several of the late-20th-century's most distinctive literary voices. It's also one of the few major Asian languages written in the Latin alphabet (a 17th-century Jesuit invention called Quốc ngữ), which makes it dramatically more approachable than its Chinese-influenced vocabulary suggests.

For English speakers, Vietnamese is hard in the same way Mandarin is — six tones in the northern dialect, five in the southern (and yes, you have to hear the difference) — but easy in nearly every other respect. The grammar is famously simple: no verb conjugations, no plurals, no articles, no cases. The Latin alphabet (with diacritics for tones) means you can read everything from day one. And the language opens up one of the most exciting countries in Southeast Asia, where any visible effort gets you laughter, encouragement and probably a free bowl of phở.