When you want to apply translations to assignment group names.
It is not possible to translate the assignment group filed name because the name field is string type (This is expected OOB).
In order to do so, you have to modify the type to "Translated text" type.
Link to the dictionary record below:
The next step will be to create translated text for the particular group name (You have to do it manually because in OOB the name type is string). Steps below:
1. For this go to sys_translated_text table and create a new record.
2. Field name will be name.
3. Table name will be Group(sys_user_group)
4. Document will be the "Assignment group name".
5. After the record has been created, you will be able to see the translation in the assignment group names.
Note:You have to make the translation text record for every group name manually.