Abstract: A portable audio recording and playback system is provided. The portable audio recording and playback system can synchronously display the corresponding lyrics or character contents, and it also can selectively record user's voice or the mixed signal of the user's voice and a background music including music and a human voice of singer during playback. Or the volume of the human voice in the background music can be increased or decreased corresponding to that of the music and be outputted or repeatedly played with changing speech speed without the tone changed for achieving the effects of on-the-go vocal and/or music accompaniment, voice recording, and language learning with changing speech speed without the tone changed.