Operation of a communication facility

For operating a communication system (1) in a vehicle (MK1) is detected at a first signal detection means a first input signal (ES1), which comprises a voice signal (SP) of a speaker (S). A work based on output signal (AS) is sent to a receiver via the communication system (1). In this case (AS) is detected at least at least one optimization value (SOV, SOD) with respect to an optimization criterion for the output signal. Depending on the optimization value (SOV, SOD) a speech optimization display (3) for the speaker (S) is driven.