The speaker device on Aibo is called speaker. The available fields are:
val: The sound to play.
playing: Equal 1 when there is a sound playing, 0 otherwise.
remain: Number of milliseconds of sound to play, 0 when the buffer is empty. The delta of this variable is 32. Useful with the ~ operator.
There is also a method available:
play(file): Plays the wav file ``file'' which is stored on the root of the memorystick.