Atomic / i18n: Unable to switch to certain site languages in Calypso

[kvvsi]

Steps to reproduce the behavior

Steps to reproduce the behavior:

1. Go to https://wordpress.com/settings/general/kvvsi.wpcomstaging.com
2. Click on Language
3. Select "Srpski (latinica)" + Apply Changes ---> Save Settings
4. See error: An unexpected error occurred. Please try again later.

What I expected to happen

I expected the site to change over to Latinized Serbian

What actually happened

I received an error and no change was made

Browser / OS version

Chrome 88, Windows 10 (2004)

Is this specific to the applied theme? Which one?

No

Does this happen on simple or atomic sites or both?

Only on Atomic

Is there any console output or error text?

No

Level of impact (Does it block purchases? Does it affect more than just one site?)

• Fairly low - only a small subset of users will encounter this, unless more languages are implicated

Screenshot / Video: If applicable, add screenshots to help explain your problem.

https://d.pr/free/v/KougPa

[dlind1]

The problem is that while we support the locale in wordpress.com, there are no core translations for it on translate.wordpress.org and the language files can't be installed on an Atomic site. The same situation could happen for any locale which is available on wordpress.com, but not available on the Atomic site in the Site Language dropdown on site/wp-admin/options-general.php page. We're currently tracking the issue in 181-gh-Automattic/i18n-issues.

[carinapilar]

Got a user request on 3974725-zen.

[martian77]

Looks like the same issue is affecting Deutsch (Sie) - see #4138652-zen.

[daria2303]

4142622-zd-woothemes