to minimize the negative consequence. Being unemotional or being diplomatic is part of the professionalism. It's hard with a second language, with different culture backgrounds but we still have to learn them either in a hard way or better in a nicer way. Try to explain your logic(the coding part) and ask for open communications on where can be a weak point. For the emotional part you can simply say you were in the middle of some other tasks while someone come up with that question, as English is not your first language it was not your intention to attribute to misunderstanding like that. Ask for what you can do to make the ball rolling.
But honestly if they're using HR for several rounds already it's very obvious they want you go. So say what you should say and do what you do but look for new opportunities. Some contract jobs are easy to find these days as a transition, especially your guys with coding skills.
Above on that, try to read some self help books on how to reduce stress, how to improve communication skills, how to improve business writing, how to make friends in the office environment etc. Those books have very easy to understand language and can improve our English overtime. Do work on skills that are working against you now. And good luck! Good health is more importantly than anything else.
