I think this song is about coping with the loss of a loved one. This is represented in many lyrics such as I think I see your face in every place that I go, and I need you here with me. To me, the reference of falling in deep is a reference of falling in a deep depression or sadness that is overwhelming and hard to overcome.
I can speak to you by saying nothing at all and there’s a pain in my heart and it won’t go away are strong references of communicating with someone who is no longer here and the overwhelming pain of dealing with and grieving the loss.
I feel like when the line you are saying the words that I want you to say is used, it is a way to show that this person lives only in their memories and they long to hear those words, the voice of that person one more time.
It’s an overwhelming and haunting song - from a person that has recently experienced 2 deaths and losses in a couple of months, this song really strikes a nerve in my heart!