A voice processing method is disclosed. The voice processing method applies first and second sentence vectors extracted from first and second utterances, that are included in one dialog group and are separated from each other, to a learning model and generates an output from which at least one word having an overlapping meaning is removed. The voice processing method can be associated with an artificial intelligence module, an unmanned aerial vehicle (UAV), a robot, an augmented reality (AR) device, a virtual reality (VR) device, devices related to 5G services, and the like.