Hi nikutaro, I’ve entered search key as to learning Mongolian language on google and founded following hint Free Language-Learning Resources Online | Transparent Language in the first place.
This site looks as though you can earn Mongolian language course for PC and also they offer Mongolian learning software for free. I’ve opened only the first hint and I’m not really sure whether it’s well. However, it’ll be good enough for the first start from my point of view. Respect for your goal and your really open mind!