You can change it and also update the translation with theUpdate Translations button. A new window
will appear, showing your language at the top - see below.
As then indicated, you will have to exit and reopen MuseScore for changes and updates to take effect.
Update translation
You can update the translation as explained above, via the preferences settings, but there is another
method:
1. Go to Help → Resource Manager
2. Click on the Update button