Hi Adam,
Sorry, I haven't a clue on how to change the language pack to do what you want. However, if you can install the Grade Me block plugin, set it up on the front page of Moodle with it configured to, Display throughout the entire site, you will benefit more. Not only will it show every teacher any assignment they are responsible for, that needs grading, it will do the same for some of the other plugins, such as, quiz, database, forum, and glossary. Back when I was actively teaching, I was able to create and add my own plugins to Grade Me, that made it list a few other plugin activities that needed to be graded. For the most part, it then just becomes for any teacher to go grade anything, from the front page, or from any course, with just one or two clicks. Best of all, no more searching by the teacher through courses for anything that needs to be graded.