ob es langsam von "falsch" zu "mögliche Variante" geworden ist, möglicherweise eine regionale Variante

Possibly, in some people’s eyes, although I couldn't say where. I’d still prefer to put it down to carelessness (conceivably ignorance) on the part of author and/or editors. It's simply incorrect. I would never let it through except in direct or reported speech if among other things a character’s speech habits are being set down. But you say that’s not the case here.

As someone who says didn't used to, I was wondering what could possibly be wrong with it until it slowly dawned on me as I was reading the first thread linked to in the OP. Got it. (Now I'm going to annoy myself in the future when I inevitably say didn't used to again.) I think related discussion: didn't used to - #7 has probably pretty much nailed it in terms of where this comes from.

#0 (OP)
Da es in meinem Buch nicht in der wörtlichen Rede auftaucht, frage ich mich, ob es langsam von "falsch" zu "mögliche Variante" geworden ist

Apparently, it's gone further than that, (and is not just a spelling error as suggested in #6). This is what Garner (Modern English Usage) has to say about the question:

The question whether the phrase should be written didn’t use to has stirred up some controversy among usage pundits. Te argument goes that didn’t supplies the past tense, and the main verb that follows should be in the present tense, as it is in a sentence such as You didn’t have [not had] to do that. But used to can be seen as an idiomatic phrase based on an archaic meaning of use (= to be in the habit of). On this view, the form of the verb is fixed in the positive used to and is unchanged in the far less common (and far less accepted) negative form, didn’t use to
In modern journalistic sources, didn’t used to is almost twice as common as didn’t use to. When didn’t use to does appear, it commonly occurs in transcribed speech—e.g.: “‘She was engulfed by a lake that didn’t use to be there,’ said Michael Foster, a case manager.” Frank Stanfeld & Lesley Clark, “Year’s Heavy Rains Still Aren’t Enough,” Orlando Sentinel, 2 Dec. 1994, at 1.

But remember the standard form that can save you headaches: never used to. It avoids the grammatical problem of did+[past tense]. It keeps used. And it doesn’t reek of dialect.

Language-Change Index [see key below]
didn’t used to: Stage 5 - Current ratio (didn’t used to be vs. didn’t use to be): 2:1

LANGUAGE-CHANGE INDEX
Stage 1: Rejected. Stage 2: Widely shunned. Stage 3: Widespread but . . . Stage 4: Ubiquitous but . . . Stage 5: Fully accepted. Ratios represent frequency of prevalent forms vs. variants in current books.

Oops. A typo when I was entering the text. It should be:

On this view, the form of the verb is fixed in the positive used to and is unchanged in the far less common (and far less accepted) negative form, didn’t used to

Danke an alle für ihre Einlassungen und Erläuterungen. Sehr erhellend!

Ich muss mich entschuldigen: Die beiden "didn't used to" kamen doch in wörtlicher Rede vor. Falls Rankin damit die sprechenden Personen charakterisieren wollte, funktioniert das ja nicht besonders gut, wenn eben kein Unterschied zu HÖREN ist zwischen didn't used to und didn't use to. Also frage ich mich, warum er das so macht. Rankin gibt zwar durchaus Lokalkolorit wieder und charakterisiert sie im Sprechstil. Ich kann mir auch nicht vorstellen, dass das Flüchtigkeitsfehler sind.

patman2, du schreibst: But remember the standard form that can save you headaches: never used to.

Was aber, wenn es (didn't used to) als Frage gestellt wird? Did he never use to ... funktioniert das?

(Das Ende des Abendlands ist nahe.) (#11)

Mindestens...

The Garner information (#10) is highly interesting. That opens up the possibility that Rankin is one of those who prefer to use the “didn’t used to” form (possibly because it’s closer to the current demotic?), or that his editor switches it in. Possibly the “didn’t use to” form is coming to be seen as in some sense pedantic (in the way, say, that the use of accusative “whom” is)?

I can see no justification for the second sentence in the view Garner cites when he writes “used to can be seen as an idiomatic phrase based on an archaic meaning of use (= to be in the habit of). On this view, the form of the verb is fixed in the positive used to.” But he is after all only citing a certain view, not arguing the point.

OED I discover lists both “didn’t use to” and “didn’t used to” (use v., senses 21b [c] and [f] respectively, first occurrence of the former listed there 1548, of the latter 1732). (The sense Garner alludes to [“archaic meaning of use, etc.”] is OED sense 22 [“rare,” most recent listed occurrence 1932].)

I’m going to be keeping my mind more open about this than hitherto. But I don’t plan to stop using the “didn’t use to” form in the near future—written and spoken.

And fwiw a couple of Ngram graphs of the two:

(1800--2019) https://books.google.com/ngrams/graph?content...

(1500--2019) https://books.google.com/ngrams/graph?content...

“I didn’t use to like it,” “Did you ever use to watch Steptoe and Son?” I don’t find either of those particularly inelegant or ugly. You could probably produce numerous examples where I might.

What I do find is that the interrogative, being fairly rare, I have to think a couple of seconds before I manage to articulate anything at all. But once I’ve got there (as above) I wouldn’t want to be without.

OT, Very much OT, but Jesse, why isn't it "misch dich lieber nicht ein"?

re #19, FWIW, zumindest das erste Zitat findet sich kopierbar hier :

https://www.novelsuspects.com/excerpts/a-hear...

 ... ‘A lovely spot for an ex-cop to go walkabout. Is this you trying to get me bushwhacked?’

‘He was coming out of a lettings agency on Lasswade Road.’ ‘Didn’t you used to own a lettings agency?’

Cafferty nodded. ‘It changed hands a few years back.’

‘And that’s his last sighting–a lettings office that used to be in your name? ...

... für das zweite gibt es leider nur https://books.google.co.uk/books?id=vjJdEAAAQ... ...

I got to my thirties before I realised that didn't used to was grammatically incorrect. Typically, it was in an English class that I was teaching at the time! Didn't use to was in the textbook, and it looked utterly, utterly wrong without the d, and it wasn't until talking about it with a fellow teacher (in her 60s) afterwards that we realised that grammatically it had to be didn't use to. It was one of those 'no way!' moments of revelation about the language you've been speaking and teaching for decades.

I reckon - Bion an obvious exception here! - that the vast majority of people simply don't know that the 'correct' form is didn't use to. I can well believe this is true of Rankin and his editors. And I don't mean this critically. I think it's just so widespread now that unless you have reason to be confronted with the 'correct' form (in an English textbook, someone correcting you, or in amw's case in #3, by reading a Leo thread), that you're not going to think twice about it.

That's an interesting statistic from Garner quoted in #10: that didn't used to is 'twice as common in journalistic writings than didn't use to'. That means two things:

(1) that there's a large number of journalists - better wordsmiths than the average Joe (but not necessarily the average Leo contributor!) - that have also never thought about the 'correct' negative form (or they have, and have chosen to stick with the more 'idiomatic' written form),

(2) the 'incorrect' form is now more prevalent in writing than the 'correct' form, and that's only going to reinforce its dominance.

I know the 'correct' form, and probably very rarely write it, but I still picture it in my head with the final d.

I don’t know enough about Rankin (the man, not his writings), but having detectives and criminals use the clinically correct “didn’t use to” form (Sorry, detectives and criminals!) might stick out a bit like a sore thumb. Who knows though if Rankin doesn’t use it in his personal (and hopefully still handwritten) correspondence … ;-)

Then there are (according to Garner above) those who argue that the “didn’t used to” form is in fact perfectly correct. See #16 paragraph 2 for my spontaneous reaction to that.

This detail that patman2 (#10) quotes from Garner is also curious: “In modern journalistic sources, didn’t used to is almost twice as common as didn’t use to. When didn’t use to does appear, it commonly occurs in transcribed speech—e.g.: “‘She was engulfed by a lake that didn’t use to be there,’ said Michael Foster, a case manager.”” I wonder what the logic is behind that.

#13 wenn eben kein Unterschied zu HÖREN ist zwischen didn't used to und didn't use to.

That might not be the case for someone speaking with the Edinburgh accent of many of Rankin's character. I don't know. And I suspect that some people might enunciate the words so that you would hear the difference. Anyway, the author knows you're reading the text, not listening to it so perhaps he's signalling something like the fact that the speaker doesn't speak "properly".

Furthermore, this article (The Puzzle of Detective Inspector John Rebus (publishersweekly.com)) features an interview with Rankin in which he says "He's 40 when we first meet him [Knots and Crosses], and 55 by the time of the latest novel. He has slowed down, aches in places where he didn't used to ache, and sees a younger, smarter, fitter world developing at his heels".

Perhaps Rankin speaks like this himself, perhaps the interviewer/editor quoted him incorrectly?

Yes, there are all sorts of possibilities with Rankin:

(a) it's used deliberately because he's trying to reproduce 'everyday' speech, and those theoretically speaking the phrase would think 'didn't used to' even if the d remains silent in speech;

(b) Rankin & editors don't know the difference themselves (and I don't think this is totally impossible);

(c) Rankin and editors know full well it's 'didn't use_ to' but have chosen not to use it either because he doesn't want to sound pedantic and fussy (as you say in #16, Bion), or because the 'correct' form will look utterly weird (and wrong) to people not familiar with it, which will be the majority of his readership.

"But used to can be seen as an idiomatic phrase based on an archaic meaning of use (= to be in the habit of). On this view, the form of the verb is fixed in the positive used to and is unchanged in the far less common (and far less accepted) negative form, didn’t use to" (Garner, quoted in #10)

I read the Garner quote in #10 to mean that this is a possible explanation for the shift from use to used, rather than a justification for it being grammatically correct. A justification for it having become widespread idiomatically, perhaps. It seems completely plausible to me: "used to" is more common in the positive ("I used to swim all the time") than in the negative or interrogative (or any other form with an auxiliary), and therefore 'used to' has somehow become a fixed expression that has slipped into the other forms and tenses.

"used to" is more common in the positive (#31)

Sure. But I read Garner's "an archaic meaning of 'use' (= to be in the habit of)" as referring not to the sense that occurs in “used to do sth.” (very extensive entry at OED sense 21), nothing archaic about it, but to OED sense 22 (“ … to be in the habit of … “) which is used absolutely: “We should, as learned Poets use, Invoke th' assistance of some Muse," and "Die at good old age as grand men use," and "I can't remember things as I used, and I don't keep the same size for ten minutes together" (OED examples).

Whatever.

(I get the impression that thanks to Selima's question the topic has received a fairly major update in the LEO archive. Can't be bad.)

Soeben auf bbc.com gelesen:

The overabundance of cheap clothes means that many of us use only 20% of the garments in our wardrobes. Meanwhile, the clothing industrywreaks havoc on our fellow humans and on the planet. But it didn't use to be like this. 

Mein Herz fliegt empor auf den Schwingen der Freude.

OP: ...frage ich mich, ob es langsam von "falsch" zu "mögliche Variante" geworden ist?

According to the ngram reader (https://books.google.com/ngrams/graph?content...), at the beginning of the tabulation, around 1800, "didn't use to" was essentially the only form used. However, "didn't used to" very slowly started gaining in usage, passing the former in frequency sometime between 1974 and 1975, and now outpacing it by a ratio of about 5:3.

@Selima: whichever version you choose, someone is sure to be unhappy with the choice. On the other hand, I expect that most readers (including myself), won't even notice the spelling, and will just glide right past it, or if we do happen to notice the spelling, we just don't care.

PS - it's like "grey" vs. "gray"; it doesn't matter: they are pronounced the same, and they mean the same.

#37 PS - it's like "grey" vs. "gray"; it doesn't matter: they are pronounced the same, and they mean the same.

I guess it matters if your name is Gray or Grey! There's a difference between Grey's Anatomy (TV series) and Gray's Anatomy (medical reference book). Have I got those the right way round?

Ich glaube, Martins #37 stellt für mich persönlich einen guten Abschluss des Themas dar. Ich denke, ich werde jetzt aufhören, mich darüber zu echauffieren.