I’ve seen this question several times in the Dynamics 365 Business Central forums recently, so in this post I would like to share some info about this issue, hope this helps.
Yes, even if Microsoft’s language pack is installed, English is displayed after switching languages.
Let me do a simple test. I installed French language (France) in my test environment.
PS: More details about How to install a Language Pack (SaaS and On-Premises)
Installation is complete.
Then go to My Settings to change the language.
You will find that the language pack has not taken effect, only the Platform has been translated. This is the same as not having a language pack installed.
Fortunately, this issue was also raised in MS Yammer by other partner, and Microsoft is already investigating.
Info from MS Yammer:
And now we’re rolling out a hotfix, so you can expect the issue to be fixed soon.https://www.yammer.com/dynamicsnavdev/threads/2089482232487936
Update 2023.01.24: Standard language pack issues have been resolved.
Hope this will help.
Thanks for reading.