That's an interesting analogy and one that I can relate to IRL. When I got a degree in languages I had been learning French for 13 years and Spanish for 4 years but I had to reach the same level in both. So it's possible, but it usually means that you were learning other stuff during the 'non-intensive' course. Since Jedi got sent all over the galaxy as ambassadors (eg Qui & Obi in TPM) or peacekeepers, I would assume that much of their training was in such things as diplomacy and 'alien' cultures. Luke didn't spend any time on that kind of thing AFAIK.