The real test is public speaking english in front of english people or people who don't speak your native language.
That is pure insanity for introvert people.
I mean you have the whole speech ready in your mind and then...at the crucial point... you're like: "... potato."
*neural collapse*
Or worse. They don't understand you and you have to repeat the sentence. The result is not better: "Yes... potato."
The other dimensions (well, to the extent that the other Myers-Briggs dimensions are worth a pot of beans, anyway) go a long way toward making up for an introvert's difficulty in coming before an audience. Roughly, they correspond to how you
know,
think, and
act. One isn't necessarily better than the other; intuitive thinkers (N) aren't necessarily better equipped than Doubting Thomases (S), or vice versa. What's important is the confidence these abilities give you, to overcome an introvert's natural stage fright.
As a public speaker,
you are the authority on what your audience came to hear; as a musician,
you are the one who can make beautiful music for them. You made all the mistakes you are going to make in writing, editing, and rehearsal. What you go out there and say, or sing, or play is exactly what you meant and exactly what they want to hear.
Edit: on further reflection, I have to admit the above is a rather strong "P" statement. The difference between J and P types, if it's real, is more important than it's given account for. To oversimplify, "J" (judging) types thrive on predictability, planning, and systematic completion of tasks. They can get lost when things don't go to plan. On the other hand, "P" types thrive on flexibility and make snap decisions that are right often enough to keep them out of trouble; they get bored when forced to follow a plan, and the best ones undermine them while getting the job done anyway.
But I stand by it nonetheless. The way to project confidence is to be confident, because you, like Zaphod Beeblebrox,
are the most important person in the Universe. Remember, you are the expert, you are the artist, your audience wants to love you, and all you have to do is let them.