Otherwise, we have to use our intuitive vision. It can also take place in a dream. Sometimes when people dream, their intuitive vision is unconsciously functioning and they can see angels. On another level, sometimes, when God wants to manifest in and through someone, he will give that person an angelic touch. Angels make themselves known to you by simple acts of kindness.
Angels have their own language.
It does not sound like an earth language. Some angels are known only by the miracles left in their paths. Some angels come from a higher planes than others. They try to help mankind. Angels do not work on the gross physical plane.