CKEditor could not change default UI language

Hi

I think this would be a bug . But i still want to know anyone could fix it ?
I have enabled the ckeditor , but i figure that the UI always show enginlish .
So i try to change it by edit " /theme/edly/ckeditor/ckeditor/config.js " , but it still not change anything .

Are there any one know how to fix it ?

Dolibarr version :13.0.2
Host : windows
Apache/2.4.41
PHP : 7.4.1
MariaDB 5.5.5