Originally the names for student and teacher could be changed in courses, I guess we could simulate it now with:

1/ empty role name means use shortname to get rolename using get_string(); if name present in role definition use format_string() that handles multilang names
2/ add role name plural field to handle plurals correctly
3/ add function get_role_name() and get_role_name_plural() and search&replace in codebase

ideas?