A portable communication device is disclosed. The portable communication device comprises a speaker adapted to be held to an ear of a user for conveying sound to the user, at least one sensor for sensing sound emanating from said sound conveyed to the user, and a control unit. The control unit is adapted to estimate, based on an electrical input signal supplied to an input port of the speaker and an electrical output signal received from an output port of the at least one sensor, a transfer characteristic from the input port of the speaker to the output port of the sensor. Furthermore, the control unit is adapted to estimate, based on the estimated transfer characteristic, a degree of sound leakage from the user's ear. A corresponding method is also disclosed.