Hey! My mother tongue is Hungarian but I study EE at a German university and of course I also use English a lot. I found that when I'm content it's easier to go with the flow, but when I'm talking normally it's harder and it does not depend on the language I use. Well in Germany everyone speaks German better than me so I think it's just stressful to talk in that situation. Confidence plays a huge role, in Germany the others speak English on the same level. There are consonants difficult than most in all three languages. Ask if you need more, hope I could help and good luck!