Regarding i18n fallback language

[Alvin Wong]

Dear Sphinx developers,

Previously, I filed an issue "When building for zh_TW, zh_CN is incorrectly used as fallback language" [1] and then a pull request "Do not add language fallback by stripping country code" [2] for fixing it. Since I have not received any response from developers, I want to bring this up on this mailing list in the hopes that someone will look into it.

Background: I am a contributor to Krita (a digital painting application, part of KDE) and I have been helping with translating its manual, which uses Sphinx, into Traditional Chinese. I noticed that Sphinx incorrectly brings in Simplified Chinese as fallback when building for Traditional Chinese, which is a big no for Traditional Chinese readers. Unfortunately, this issue is blocking us from deploying the Traditional Chinese translation of our manual.

We also suspect this issue may affect Portuguese and Brazilian Portuguese, as well as several other languages.

I would really appreciate any comments on this pull request and hope the developers will consider merging it. If there are any concerns with the pull request, please let me know and I will be happy to address them.

[1]: https://github.com/sphinx-doc/sphinx/issues/9634

[2]: https://github.com/sphinx-doc/sphinx/pull/9635

Best Regards,

Alvin Wong