I heard that warning only once when my batch mate was doing his base flight and pitch up a bit too violently to lower the ROD during base leg and thus triggered the warning. From what I understand , in that case the warning can be stopped by either lowering the nose to recover a positive flight path angle and most likely an increase in airspeed or adding power which will also increase the speed. I don't see any situation where increasing the speed won't solve the problem. Therefore the Auto Call Out " Speed Speed Speed" does make sense to me.