answer:Strictly speaking, Chinese doesn’t have X and Z. Westerners have come up with several different systems for writing Chinese using the Roman alphabet, but there’s quite a bit of disagreement among the different systems about which Roman letters best represent certain Chinese sounds. For instance, in the Hanyu Pinyin system, you’ll see lots of “X“s. The Wade-Giles system will use “hs” to represent that same sound, and the Gwoyeu Romatzyh system will use “shi”. Where Hanyu Pinyin uses “z”, Wade-Giles uses “ts” and Gwoyeu Romatzyh uses “tz”. And that’s just three of the commonly used systems. There are plenty of others. All of them are just coarse approximations of the actual Chinese pronunciations.