The letter Q pronunciation and Chinese language

[LUNN]

Why is the letter Q which sounds like KEW, being used for Chinese with CH sound, example Qinghai = Chinghai, Urumqi = Urumchi, why dont they just use C and H for this purpose instead of misusing Q.

Similarly ZHOU as in GUANGZHOU and other cities is pronounced as JO or GUANGJO, so why use ZHOU.

[HalcyonDays]

It's a transliteration convention. In other words, the problem is that you have to transfer a language with a different alphabet into roman/latin letters. There has to be a recognised system for dealing with this. In Chinese it's called 'pinyin' for transliterating mandarin Chinese into our roman alphabet. I don't know why the 'ch' sound becomes 'q', but it does, and it's a system, and so there we are.

The pinyin system is supposed to be more accurate than the old system for transliteration that was followed until several decades ago. It's why we used to have Peking instead of today's Beijing, or Mao Tse Tung versus Mao Zedong. However, we still have PEK as the IATA designator for Beijing.

Arabic has similar problems, but there is far less consistency - hence we get numerous spellings for the name Mohammed.

[TheRealAncientMarine]

Why is the letter Q which sounds like KEW, being used for Chinese with CH sound, example Qinghai = Chinghai, Urumqi = Urumchi, why dont they just use C and H for this purpose instead of misusing Q.

Similarly ZHOU as in GUANGZHOU and other cities is pronounced as JO or GUANGJO, so why use ZHOU.

Because ch is pronounced different from q and zh different from j, if you're Chinese. If you're American you don't give a shit and the Chinese don't give one either since they do not understand you.
Otherwise, see HD's excellent explanation.
Also check out Wulumuchi.
Per

[Bok269]

IIRC when pinyin was developed early in the 20th century, the Chinese consulted with the Russians, hence q and x sounding like a ch/j sound