On Learning the Native Language

So I had fun with Japanese today at my base school. I was looking at I-sensei's papers and noticed he made a grammar mistake. I fixed it, then felt bad. He's studying English really hard, and I'm not studying Japanese. So I got motivated to study Japanese. When we got back to the teachers room, I started studying my Japanese book and got quite far. Towards the end fo the day, though, I came across something that confused me. Basic explanation. In my Japanese class at Owens, sensei (and the textbook) taught us that "benkyo o shimasu" is "to study" or "I study". The books that JET gives us, though, says it should be "benkyo shimasu". So I asked my head English teacher which was right. She thought about it and said both phrases quite a few times, but she couldn't figure out the difference. She asked the science teacher sitting across from her. Both teahcers started saying both phrases and were both getting confused. The principal walked by at that time, and overheard them, so he asked what was up, and my English teacher explained. So he started trying to think which was phrase was better (it should be noted that it's VERY hard for a non-native Japanese speaker to hear the difference between the two phrases, so it almost sounded like they were just repeating some sort of odd mantra about studying). The Vice Principal then came over to see what was up, and he joined in with his INCREDIBLY loud voice. The art teacher wandered up the aisle trying to get to his desk and got caught up in it, too. To make a long story short, eventually we had about 10 people crammed in the small aisle between my English teacher and I. Quite fun. And the teachers never came to a consensus about which was more accurate. They even asked a Japanese teacher, and she wasn't sure. The confusion lasted for about 15 minutes.

I eventually looked up at the principal and said, in a very exasperated way, "benkyo o shimasen (I do NOT study)" and closed my book, slamming it on my desk. He laughed and said "benkyo shimasen"?. I rolled my eyes (in retrospect, rolling your eyes at your boss is probably not the best idea I ever had, but he laughed because I was attempting to use Japanese to express my frustration) and said, "Nihongo wa muzukashii, ne? Eigo was yasai" (which I thought meant "Japanese is hard, right? English is easy" but which ACTUALLY meant "Japanese is hard, English is a vegetable". I think he understood what I meant.) After laughing, he put on a serious face and said, "Hai. Nihongo wa totemo muzukashii desu. Ganbatte." ("Yes, Japanese is very difficult. Good luck.") I smiled and then put my book in the trashcan, saying, "yaku ni tatanai" (useless!). He laughed and agreed that that was where it belonged.

Now I'm rather discouraged about learning Japanese. If even the native speakers have no clue what's going on, how do I have any hope of learning it? On the other hand, I did manage to be slightly cheeky, bordering on sarcastic, using only a few, simple words. So maybe there is hope yet.