If I'm not mistaken, you should be able to scroll through dialogue to see the conversation log, but that might just be with NPCs. I haven't played co-op since the Alpha though, so I could be wrong.
I remember that there was a bug where I could never see the final response in a co-op conversation because it ended before I could read it.
Last edited by Hurix; 21/04/14 12:50 AM.