How to interrupt in English?
There are situations in life where you need to interrupt, even if it might seem impolite or be socially awkward.
Interrupting can be difficult enough even in your mother-tongue, so obviously it becomes twice as complicated in a second language.
Maybe an interruption is necessary because a friend is talking for too long and being boring. In that informal situation, you can just butt in and talk more loudly than the other person.