As an introvert, talking to strangers is in my comfort zone. Being an introvert has nothing to do with whether I'm able to talk to strangers.
As an introvert, speaking up in small groups isn't a problem. I do it all the time when I feel like it or when I feel it's necessary. Again, what does being an introvert have to do with this?
As an introvert, I regularly find myself leasing things because other people don't want to step up. This has nothing to do with introversion/extraversion.
As an introvert, I do talks in front of an audience. Not a problem.
Learning all this was valuable, but none of it solved my introversion. Because it's not something that can or needs to be fixed.
What it did fix was my shyness, lack of confidence and insecurity around other people. But I'm still introverted because it still requires me to exert a lot of energy, which can only be regained if I'm alone.