I know about Chinese phonetic alphabet system. It's only applies to Mandarin not Cantonese. As for the Chinese radio station, they will speak Mandarin or Cantonese depending on the program and have a recorded announcer in English such as "You're listening to KQEA-LP San Francisco" on the top of the hour and go back to Chinese language after that. When I learned Chinese, I didn't use the phonetic alphabet system Pinyin in Mainland China, BoPoMoFo/Zhuyin in Taiwan. I had to memorize Chinese Characters, I took Cantonese when I was a kid and we didn't use the pinyin system when we learned Chinese Characters.Chinese doesn’t have an alphabet per se. It has a series of initials and finals that make up its words. Several forms of romanization have been introduced to help those of us who natively speak a language with a Roman alphabet learn it, but the ultimate reason you learn romanization when learning Chinese is to get rid of it. A phonics-based system called BoPoMoFo is, or at least used to be, somewhat popular in Taiwan, but, as far as I know, it has never been widely used anywhere else. Plus, it doesn’t resemble our alphabet in any way, shape or form. I actually found learning it very difficult and frustrating and quickly ditched it in my junior high years. I replaced it with PinYin, which is a form of romanization, and a focus on learning a simple book of characters so I could expand from there.
I suppose you could try to use the initial and final sounds for some call letters as there are some call letter combinations that would correspond to exact initials and finals, but it would likely sound awkward or like gibberish to a native speaker. So, you might as well ID in English.
As for pronouncing latin letters, they use the English pronunciation even in China when you have to spell out in pinyin. They don't use French, Italian, Spanish alphabet pronunciation. As for Hong Kong since English is co-official with Chinese (Cantonese) they use English pronunciation when it comes to roman letters.
As for Top of the hour ID call letters when it comes to language. FCC doesn't have a language requirement. Also, The United States doesn't have an official language.
