Chinese Pinyin 3rd-tone diacritical mark in OS High Sierra
Users who speak both Chinese and English, help! On my old Mac, pressing "Option" and "v" together, then a vowel, allowed me to type a vowel with a "v" on top of it, which is how the third tone is written in the Hanyu (Chinese) Pinyin Romanization system. On my new MacBook (OS High Sierra), when I press "option" and "v" together, I get a square root symbol instead. How do I write vowels with a "v" diacritical mark on top in this new OS?
MacBook, macOS High Sierra (10.13.6)