As admin enable the multilang filter for content and headers. As admin, install a second language, e.g. German. As trainer, set up a course and set group mode to "Separate groups". Enrol two users. Create two groups named '<span class="multilang" lang="de">Gruppe</span><span class="multilang" lang="en">Group</span> A' and '<span class="multilang" lang="de">Gruppe</span><span class="multilang" lang="en">Group</span> B' and assign one user to each group. Create an assignment activity. Go to Grades → Single view and choose "user" Verify in the Group chooser "Group A" and "Group B" is visible. Do choose "Group B" Verify in the Select separate group information "Group B" is visible.