You can see the vertical axis is the load factor, and the horizontal axis speed. The stall speed at various loads is the curve marked "
accelerated stall", and it runs up until meets the load limit for the particular airframe.
The idea is: Pull back on the stick below this meeting point (
the manoeuvering speed), and the wing will stall, thus unloading it, before it over-stresses. Pull back on the stick above this speed, and you will overload the wing before it can stall ...
If you lower the limit load, then the intersection runs down the curved stall line to a lower speed.