Abstract: In a system with a display and an input device, a graphical user interface (GUI) may be presented via the display. A natural language understanding engine may be applied to a free-form text documenting a clinical patient encounter, to automatically derive one or more engine-suggested medical billing codes, which may be presented in the GUI. User input may be accepted to modify the engine-suggested codes in the GUI, resulting in an unfinalized set of user-approved codes for the patient encounter. The natural language understanding engine may be adjusted using the user modification of the engine-suggested codes as feedback, and the adjusted natural language understanding engine may be applied to automatically derive a second set of engine-suggested medical billing codes for the patient encounter, which may be presented for user review in the GUI before finalizing coding of the encounter.