A two part question. Are there attested historical changes whereby a construction C in some language means 'not yet', and then C changes in meaning so that it means 'not again' at a later time (or vice versa)? Second, can someone situate such an alternation, real or imagined, within some theory of negated scalars, viz. Horn's A-I-E-O square?
Informally, one meaning refers to an action which has happened at least once before the reference time, and will not happen at any time after the reference time, and the other refers to an action which has not happened at any time before the reference time, but will happen at least once after the reference time.
Or, as I have thought about it now, it is a change between NOT(still(p)) and still(NOT(p)).