Prerequisites Add a second language pack to your Moodle instance, e.g. Russian ("ru"). In Site administration > Development > Debugging, enable Developer debugging mode. Create a course, C1, and enrol a student in the course. Test As admin, go to Site administration > Plugins > Filters > Manage filters. Activate "Multi-Language Content" filter and select "Content and headings" under "Apply to". In a course, add an assignment with title <span lang="EN" class="multilang">TITLE ENGLISH</span><span lang="RU" class="multilang">TITLE RUSSIAN</span> having as due date tomorrow. Add the calendar block to the course if it isn't yet. Log out and log in as the student. Access the course and hover the due date of the assignment on the calendar. Verify the popup does show only the English title "TITLE ENGLISH". Go to the Dashboard. Hover the due date of the assignment on the calendar. Verify the popup does show only the English title "TITLE ENGLISH". Confirm you don't see any warning, error or notice.