Why we don't talk right away

I have a thought as to why we don't talk right away in acting class. I think that it is much easier to convey a message if you are speaking. You could easily tell if someone was hurt, angry, or upset just by what they were saying. When acting, the hard part is making what you are doing believable. In real life we do talk, but we also use body language such as facial expression, movement or gestures to communicate. Sometimes when acting we can forget about these things (details) and just try to convey our message through spoken words, when in actuality that is not at all how it goes down. It is important for use to first be able to take advantage of the details that can be conveyed through body language, then it will be much more believable when we add words.