(OT) (ISO)
Chinese Hong Kong ZHH zho
Chinese Phonetic ZHP zho
Chinese Simplified ZHS zho
Chinese Traditional ZHT zho
you are comparing apples and oranges ,as the _expression_ goes. The ISO language codes and BCP47 are about languages.
The table from teh OT spec is NOT a language idfentifier. It identifies what the OT spec refers to as a language system. According to the spec:
"Language system tags identify the language systems supported in a
OpenType Layout font. What is meant by a “language system” in this
context is a set of typographic conventions for how text in a given
script should be presented. Such conventions may be associated with
particular languages, with particular genres of usage, with different
publications, and other such factors."
The language system tag could map to one language, to multiple languages, and in unexpected ways. Grouping commonalities in orthographic representation and typesetting traditions are the core aspect as far as I can tell, rather than language identification.
At least thats my partial understanding.
Andrew
-- Andrew Cunningham Vicnet Research and Development Coordinator State Library of Victoria Australia