Clary wrote:As JTT is the champion of usage, his 'didn't used to' appears to be favourite for the future. However, I keep on saying 'used not to' in my fogeyish way.
Clary,
Your choice is fine and I cannot comment on how 'fogeyish' it may be for I'm not that familair with BrE usage. Quite obvioulsy there are dialectal differences at play here and there may well be age differences also.
Any sensible person champions usage as a measure of correct language for there is nothing else that can guide us in language use.
The trick is in keeping certain uses reserved for certain registers. That's where these prescriptivists have erred [and continue to err] so badly in describing language. Well, there and a number of other areas too.
What was it that the linguist Dwight Bolinger said? Let me google it so I don't mess it up with a paraphrase. ... , ... ,
I found it.
"Usage in the broad sense is always the determinator of correctness. The only way to falsify that assertion is to imagine that language somehow preceded its users ..." (D Bolinger)