Expose other users’ default/primary language

[j-f1]

Pitch

Add a new language property to users, make it available via the API, and federate it over ActivityPub.

This property could be sourced from the “Interface language” preference, or it could be a new setting in the profile settings.

When reviewing the specs to see if there was already such a property defined in ActivityPub, I noticed that there appears to be an @language property in one of the examples, so other projects may already support this feature.

Motivation

Currently, posts have a language property attached, which allows clients to process text correctly based on the post language (for example, by using appropriate character rendering for code points that differ between fonts, or to tell a screen reader to switch to a voice that is capable of reading the language properly). However, there is no similar property available for profiles as a whole. Ideally, the profile language property would allow clients to render the display name, bio, and profile metadata in the appropriate language.

Screen reader users would benefit most directly, since the screen reader would be able to correctly pronounce the words in the bio. But lots of other people would benefit. For example, Han unification means that differently-rendered characters in different East Asian languages share a codepoint. Allowing people to specify their language would make it possible for clients to render such characters correctly.