Specifically for languages, I think Audio Recorder is worth a mention:
I agree with the other comments that anything that makes teachers' admin and assessment tasks easier is likely to make them prick up their ears. Let's not forget the fundamentals like the grade book and how useful it can be for teacher, peer, and self assessment in the core Moodle activities (Forum, Glossary, Assignment, etc.) otherwise continuous assessment can be a massive undertaking. And making everyone's work, records, and grades available any time, anywhere and options to give learners and parents access to those can be advantageous.
How about the communication features? Like being able to send messages/emails to groups of learners. On going discourse between learners and mentors, i.e. learners/mentors can review their histories of interactions with each other. Great for reflective practice and reflective inquiry, personal learning plans, etc.
Moodle's course layout is unbeatable in my opinion; possibly one of it's strongest features but one that Moodlers seem to take for granted.
For larger organisations that have ongoing professional development programmes for their teaching staff, OpenBadges can offer a way of formally recording participation and awarding qualifications that other organisations might recognise. It'd certainly be more meaningful than traditional reference letters.
Personally, I don't like the PDF format per se. Online text writing assignments offer greater flexibility and more practical support for multimedia; images, audio, video, and animations. Teachers and mentors can give detailed feedback and can integrate it with other activity modules such as the Glossary module. Although the value of corrective feedback with regards to second language acquisition is questionable, most teachers and institutions still swear by it and Moodle can offer ways of making it more helpful to learners (explicit, meaningful, and coherent) and less labour intensive for teachers and mentors. See: http://blog.matbury.com/2012/03/01/using-moodle-for-written-corrective-feedback/
Then there's the SWF Activity Module for deploying engaging multimedia learning interactions. However, I don't think the branch for Moodle 2.5+ will be ready in time for your presentation.
And finally, by far THE biggest advantage that Moodle has is its community. Need help? Want to know something? Want to get some feedback on an idea? Here it is for free from a wide range of qualified, experienced educators and developers.