A sleep teaching aid apparatus 1 is disclosed comprising: a microphone 10 for converting received noise into an audio signal, memory means 22 for storing an audio playback message for output through a loudspeaker 8 and processing means 20 configured to monitor the received audio signal and to trigger a first timer or counter upon detection of the volume exceeding a predetermined threshold. Upon reaching a predetermined first time period or count, the processing means is arranged to cause output of the playback message through the loudspeaker, the first timer or counter being reset if before the time period or count is reached the detected sound drops below the threshold for greater than a second time period which is less than the first time period or count.
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