The interplay between di-oraisa and di-rabbanan. A FASCINATING topic. It is worth much more time. This is just a taste.
A woman giving a speech in front of men. I don't think it will change anyone's practice. One part of the observant world allows it while the other doesn't. But that is sociology. What is HALACHA?
As usual - a link doesn't imply consent or dissent unless I say otherwise.