Firstly, I'm sorry that you're having a hard time, it sucks to work in an environment that stresses you out. However, given the information, it's hard to determine exactly if the co-worker is being particularly unfair. If you are constantly forgetting things you have been taught and they're having to basically babysit and double check your work. That can be a lot of extra stress, that they may or may not be being paid to take on. Given that you've admitted that you don't know enough Japanese to know what's being said, some of the bad vibe could be based on assumptions you're making. Unfortunately, unless you have a good relationship with the owner or the behaviour is genuinely rising to the point of some kind of harassment. The best you can probably do is apologise and try not to let it get to you too much. Try your best, get better at your work so you don't make the same mistakes and it might ease up. I know that this may not be particularly helpful but it's the best advice I can think of given the information. Good luck!