Our “souls" travel to the Astral dimension when we sleep. The “language" of the Astral dimension is symbolic. This is why what we “dream" about is symbolic too. What we see, who we meet, what we do and what happens in dreams is symbolic. These should not be interpreted literally. They symbolize something within us. If you meet someone in a dream, it does not necessarily mean you met THEM. They simply represent something within you. For example, dreaming of being crippled may mean that you are feeling incapable/limited in an area in your waking life. Dreaming of flying may represent a feeling of freedom/achievement in your waking life.
Most people travel to the Astral in a subconscious/unconscious state when we dream. We do not actively participate, rather, things happen to us in dreams.
Some people have mastered the art of lucid dreaming or Astral projection where they consciously participate in their dreams. They travel to the Astral as if they are in the waking state. They consciously decide what to do and where to go while dreaming. The “language" still remains largely symbolic but for them, they may actually meet and interact with another soul.
Most people however, are not even aware they are dreaming and only realize this once they wake. They wander in the Astral in a “sleep" state and do not realize where they are.