The standard pronunciation of Putonghua is Ji à o.

Such as: fermentation (fā jiào)

The writing and pronunciation of characters is a convention, and it will change. Such as oblique (xié) ancient reading xiá；; Wild (yě) ancient reading y m: Ride (qí) ancient books, read, etc.

The pronunciation and regulations of Hong Kong and Taiwan are different from those of Mandarin, or slightly different, so it is not wrong to "ferment" and pronounce "fā xiào". Another example is the opposite direction, reading in Mandarin: nán yuán běi zhé, and reading in Taiwanese: nán yuán běi chè.

Therefore, the language often does as the Romans do, except for the specification requirements.