Teams initial language settings
Currently, the initial language of Teams depends on the base language of the OS.
For example, even if I apply the Japanese language pack, the base language of the OS is English, so the initial language of Teams will be English.
If the user has to change the language manually and has a large number of employees, this can be a huge effort.
So, please fix that refer the application status of the language pack.
sho takezawa commented
Note: We are usig the image of the Globally OS , and the OS-based language is English.
Regionnal IT is applying language packs that appropriate for each region.