Loads a locale's pack if the page has not, so a reader who chose a language
hears it without the page author having added a script tag.
English needs no pack. A pack already registered, in flight, or present as
a script tag is not fetched again. Resolves to whether the locale is loaded
once the attempt settles; a page with no locatable pack directory resolves
false with one warning, and MAIDR keeps speaking English.
Loads a locale's pack if the page has not, so a reader who chose a language hears it without the page author having added a script tag.
English needs no pack. A pack already registered, in flight, or present as a script tag is not fetched again. Resolves to whether the locale is loaded once the attempt settles; a page with no locatable pack directory resolves false with one warning, and MAIDR keeps speaking English.