1. language: if the interviewer brought up the language issue, my guess would be it is an issue, although you may not agree. Try to speak slower, with every word pronounced correctly and clearly. 其中我说的一两个词他们表示听不懂，我不得不给他们写下来。that's not acceptable and it only flags communication problem down the road. Start working on this, it can be improved with a lot of efforts.
2. confidence: you don't sound confident, so I assume you didn't act confident during interview. Remember, even if you don't have enough experience or skills, you should act as if you did, at least you should have the ability to learn. If a person has no confidence in herself, how do you expect others to trust her?
Good luck! You will find something.
