Can humans communicate their feelings to each other without talking?
Yep. If you see someone crying you know something is up. If they are smiling while crying they are tears of joy, if frowning they are sad. Through facial and expressions and body language and actions you can pretty much tell.
Ya.. through their face expressions
yea facial expressions, hand movements or gestures, face color
yes. body language & facial expressions. do you consider writing talking?
Yes, the vast majority of human communication is non verbal.
Sometimes just that "look" or the eyes says it all! Even the dog gives you that "look' when a "bad doggy" occurred. :)
yeah with eye contact me and my friends bf do it all the time
All of the above and a middle finger.
Yes, we're very good at body language.