> Even static text can refer to dates. And while ISO 8601 really is the proper unambiguous way to refer to all-numeric dates we still have the British and most of rest of the world preferred way of day-month-year, whereas with American English the preferred way is month-day-year.

It is really only an issue for all numeric dates. If you put the month in words, everyone gets it regardless of the order. Everyone understands that ''4 July'' and ''July 4'' (or ''July 4th'') are the same thing. In fact, in British (and Australian) English, at least, both ways are strictly speaking correct. Month-first is viewed as somewhat old-fashioned but still encountered especially in some very formal contexts. (Actually, a lot of American-British differences are due to American English being more conservative, and failing to adopt changes in the language which later occurred in England, and the differences in date order are an example of that)

> And likewise, if you are writing for an Australian audience then the assumed currency when you say naked “dollars” will be AUD. Whereas text for Canadian audiences will have CAD being the assumed meaning of naked “dollars”.

As an Australian I have no trouble working out what "dollars" means based on context. I will assume it means US dollars unless I am reading an Australian website (or Canadian or New Zealand or so on). Formally tagging the website with a locale is pointless for this. Anyway, one can always be explicit (USD vs AUD or US$ vs AU$), and in my experience a lot of texts are. Explicitness is always the best when dealing with international audiences. And, commonly, Australian news sources will, when reporting international news, give the foreign amount first (USD or EUR or GBP or JPY or whatever) and then an Australian dollar conversion in brackets. (I expect Canadian and New Zealand news sources would do the same thing.)

> And that’s why I mean that there often is a locale tied even to text.

Often, when talking about texts, house style is a more important concept than locale. For example, the United Nations (and its agencies) has its own rules about spelling English words, they mostly follow American conventions (e.g ''World Health Organization'' not ''World Health Organisation'') but sometimes use British spellings instead (e.g ''United Nations Environment Programme'' not ''United Nations Environment Program''). I don't know if you can easily map an organisation's house styles to locales.

The other problem is what is in a locale is often disputed. For example, what is the first day of the week in Australian locale, Sunday or Monday? There is actually no consensus on this question in Australian culture. My wife and I can't agree on it, and even Australian media reflects the lack of consensus [0]. However, interestingly, while the ABC (our national public broadcaster) says the official answer is Monday, Unicode CLDR says Sunday, and most software vendors have followed Unicode. But, Unicode CLDR actually used to say Monday, and someone talked Unicode into changing it. Maybe I should try to talk them into changing it back :)

[0] https://www.abc.net.au/news/2019-08-18/which-day-do-you-cons...