I know this question has been asked before but I’d like to add on.

Do diplomats (or politicians visiting / having forums or conferences etc) speak in English when they meet diplomats from another country?

What if the diplomat doesnt have fantastic grasp of English?

If interpreters are being used, does that mean that these certain nuances and terms get lost within the interpretation? Since there are certain nuances and terms that simply cannot be expressed with using another language. Additionally, expressions / emotions can potentially get lost during interpretation. Do interpreters interpret in the most neutral way possible, or do they have to convey these expressions and emotions to the best of their abilities?

Can a misinterpretation / misunderstanding happen because of how the interpreter interpreted, and how the diplomat interpreted the interpreter?