There is not translation support email Notification records which means that the ServiceNow Email UI will be translated but not the Contents of the email.
Creating a Language depended Notification Record
The only way to get the translated notification is to have multiple notification records and send based on the recipients language,
Condition: Assigned to.Language | is | English
Please Review for more information: https://community.servicenow.com/community?id=community_question&sys_id=0ce7472ddb1cdbc01dcaf3231f961918