A sound accessory device comprising: - a receiving unit to receive a sound; - a sound output unit to output a sound; and - a control unit to receive at least one sound through the receiving unit; to set the at least one sound as at least one sound for triggering a sound output control, to receive a sound signal from a first external device, connected to the sound accessory device, through the receiving unit, to control the sound output unit to output a first sound using the received sound signal to receive a second sound generated by a sound source from an external environment through the receiving unit, while the first sound is output by the sound output unit, to determine whether the second sound is one of the at least one sound for triggering the sound output control by comparing characteristics of the at least one sound for triggering the sound output control with characteristics of the second sound, and to output the second sound if the second sound is one of the at least one sound for triggering the sound output control, wherein the at least one sound for triggering the sound output control comprises at least any one selected from a specific word, a voiceprint representing a speech of a specific person, a horn of a vehicle, an alarm sound, a notification sound of an external device, a sound of an animal, and a doorbell sound, wherein the characteristics of the second sound comprise at least one selected from frequency characteristics, a zero crossing rate, average spectrum, spectral flatness, prominent tones across a set of bands, and a bandwith, and wherein the control unit is adapted to control the output of the first sound according to a type of the second sound. - a receiving unit to receive a sound; - a sound output unit to output a sound; and - a control unit to receive at least one sound through the receiving unit; to set the at least one sound as at least one sound for triggering a sound output control, to receive a sound signal from a first external device, connected to the sound accessory device, through the receiving unit, to control the sound output unit to output a first sound using the received sound signal to receive a second sound generated by a sound source from an external environment through the receiving unit, while the first sound is output by the sound output unit, to determine whether the second sound is one of the at least one sound for triggering the sound output control by comparing characteristics of the at least one sound for triggering the sound output control with characteristics of the second sound, and to output the second sound if the second sound is one of the at least one sound for triggering the sound output control, wherein the at least one sound for triggering the sound output control comprises at least any one selected from a specific word, a voiceprint representing a speech of a specific person, a horn of a vehicle, an alarm sound, a notification sound of an external device, a sound of an animal, and a doorbell sound, wherein the characteristics of the second sound comprise at least one selected from frequency characteristics, a zero crossing rate, average spectrum, spectral flatness, prominent tones across a set of bands, and a bandwith, and wherein the control unit is adapted to control the output of the first sound according to a type of the second sound. to receive at least one sound through the receiving unit; to set the at least one sound as at least one sound for triggering a sound output control, to receive a sound signal from a first external device, connected to the sound accessory device, through the receiving unit, to control the sound output unit to output a first sound using the received sound signal to receive a second sound generated by a sound source from an external environment through the receiving unit, while the first sound is output by the sound output unit, to determine whether the second sound is one of the at least one sound for triggering the sound output control by comparing characteristics of the at least one sound for triggering the sound output control with characteristics of the second sound, and to output the second sound if the second sound is one of the at least one sound for triggering the sound output control,