Dealing with anxiety about answering questions during presentations
There are other questions about &quot;imposter syndrome&quot; on this Stack, it might be useful to look through them because some of what you describe might fit into that area.
Besides that, I think the best way to feel better about answering questions during presentations is to do it a lot. Seek out opportunities to present to a &quot;friendly audience&quot;, and ask that they challenge you with questions. Talk about your research informally with fellow students in your area. Do all of this in English, in case you typically use another language in those contexts.
You can also try to plan ahead for certain questions or areas of questions, and even make slides to respond to those questions ahead of time if they are asked. Generally I wouldn't suggest purposefully leaving information out to prompt certain questions, but it is rare that you can fit every single caveat and counterexample and piece of background into a talk.
If you can't figure out what question someone is asking, try to ask it back to them, even if you are off the mark or don't get it exactly right - that's usually more productive than just asking someone to repeat. I see native English speakers including everyone from students to full professors have trouble understanding what someone is asking about all the time - it's quite normal. Also, questions asked during a talk aren't like exam questions where a grader is judging your answer based on some rubric for that specific question. Usually the asker is hoping to get you to elaborate on something, so even if all you can pick up is a key word you can repeat back a possible question based on that key word, or just start elaborating on that area. I'm also a fan of being honest with language difficulties. I would never think less of someone who just gave an entire talk in their non-native language but doesn't understand a particular word or phrase I used.
Lastly, I don't think academia is nearly as &quot;judging&quot; as you may think it is. Especially when you are presenting your own work, know that you are the best expert in the world in your own work. PhD-level research does build on what has been done before, but ultimately if it's research worth doing as a PhD student it is pushing some boundary of knowledge. You're the only person who has yet crossed that particular boundary, and the whole point of giving an academic presentation is to bring your colleagues up to speed.