How to analyze word frequency in Coda or specific Docs?

I understand the requirements quite clearly. Since there is no apparent way to use native formulas to access Section texts, and there is also no API support for accessing text sections, you have to do pretty much what I said earlier:

Note - while there is certainly a Pack for Google’s NLP service, there’s no [apparent] way to utilize this Pack with section [document] text; formulas are limited to accessing data tables and their fields as far as I know.