Mainland China uses the pinyin system to write Mandarin words and names with English letters.​Pinyin isn't used in Cantonese or other Chinese dialects, and it's not as widely used in Taiwan. China officially adopted pinyin in 1958, and earlier emigrants also spelled their names differently. Pinyin wasn't designed to be intuitive for English speakers, and it's common for our first guess to be so far off the mark that a listener can't even recognize their own name. An hour or so of effort is enough for most English speakers to pronounce Mandarin names poorly-but-not-incomprehensibly, similar to how we try our best with French or Russian.