Airspeed Low Alert
On airplanes with Airspeed Low aural, an alert "AIRSPEED LOW, AIRSPEED LOW" provides the flight crew with low airspeed awareness. The aural annunciates when the current airspeed decreases into the minimum maneuver speed amber bar.
The aural coincides with the low airspeed alert on the airspeed indication.
B737-NG FCOM VOL 2 15.20.23
I believe its a optional extra on the EGPWS... this is on the NG...