Learning Thassilonian Language

[Outl]

Archives of Nethys lists Thassilonian as an Uncommon language, and it is also marked as a Regional language. BTW, AoN marks 27 languages as Regional, but the Regional Languages table in the CRB only mentions 9 of them.

If I create a character from New Thassilon, does it have access to the Thassilonian language?
If I create a character with the Thassilonian Traveler background, does it have access to the Thassilonian language?
If I use a certain boon to create a character with the Time Traveler background from that nation, does it have access to the Thassilonian language?
If I create a character from Saga Lands, does it have access to the Thassilonian language (because of World Guide page 108)?
If a character takes the Multilingual feat, can it learn the Thassilonian language?

Some folks seem to think all five answers are yes, some think all five answers are no, and there are some in-betweens.

Is it possible to get an official answer that's more than a guess?

[Xathel]

If you want an unassailable source for knowing Thassilonian, take the Thassilonian Delver legacy background. It explicitly grants knowledge of the language, but requires that you have played a minimum number of scenarios from (IIRC) Season 4 of 1st edition PFS.

(My Thassilonian Delver PC also wanted to learn Azlanti, which has similarly confusing access requiremehts. Until I'm told otherwise, I'm going to assume that the World Traveler [High Seas] boon to get access to Azlanti, and Multilingual to learn it, is sufficient.)