Deceleration into stall - illuminating discussion.
Using the awareness of this 1 knot per second deceleration to find the stall during testing - about delta-g=0.5/9.8=0.05 - illuminates the answer brilliantly. Added on to the downward acceleration as the lift drops associated with the stall.
It's obvious when presented so plainly, yet the picture conjured up by "a stall" is of something happening with almost no changes leading to it, which is also strange when you think about it, since it's obviously something caused in response to changes in circumstances.