Achivement name are always written in english when unlocked on Nintendo Switch.

When unlocking an achivement, the achivement name is always written in english (when shown on top of the screen).

How to do it:

1. Connect to a Microsoft account if you’re not.

2. Play a World with achivement on.

3. Unlock any achivement like take inventory or getting wood.

4. The achivement take a very long time to show (See here: https://report.bugs.mojang.com/servicedesk/customer/portal/6/MCPE-240248) and his name is in english no matter what.