It would be quite unorthodox to complete a Diploma in Languages without cross-crediting subjects from your breadth, as you would be required to do the two completely separately. In other words, I feel as though you're not 100% sure how the Diplangs are normally completed. A common misconception holds that one will normally complete the diploma as a form of educational enrichment on top of their own faculty and breadth subjects; this is for the most part untrue, as it would mean that you would be completing 62.5 credit points per semester (which is extremely challenging, especially in biomed, and logistically quite difficult to work out).
Similarly, you should sit down with a course planner from Stop 1 to work out which subjects you'll be doing, as the planning around a diploma is a lot more complicated than the handbook and website give off. In particular: it is advised that you start your diploma after/during 2nd year, or else you might have to pay up-front. My advice would be to either pick one of German or French to do as your language, and then decide if you want to cross-credit your breadth subjects towards a diploma later down the track. Hope this helps.