Obviously, this is little more than a thumbnail sketch. Lang's book entitled, Unconscious Communication in Everyday Life (Jason Aronson Press), gives many down to earth examples of 'encoded messages'. Even though it was written for a general audience, the psychotherapist can easily place the information in his or her own context. Also, Langs developed 3 workbooks published by Newconcept Press called Workbooks for Psychotherapists, which offer an in depth look at the actual methods.
What I find interesting is that you need not accept this lock, stock and barrel (so to speak!), but the essence of these ideas are very interesting... and we need to keep a careful ear out for encoded messages no matter what our basic organizing principles for listening may be. Reading Langs makes one much more sensitive about what we say and do and how this will have immediate effects on what we hear from our patients (clients or whatever). One can see why Langs discards transference and countertransference as useful terms, because they ignore what is an everpresent ongoing influence of messages moving between two participants in a dialogue. He speaks as well of the powerful influences of frame issues-- how cancellations are discussed, changes in appointment times, the use of recording devices, vacations, extensions of time etc--- and how each of these often provide a nucleus (an adaptive context) around which uncon communications will be organized in subsequent therapy sessions.