[QUOTE=galt]
There’s no need to be rude. You didn’t actually say that in your previous post. But now that you have, I see your point.
Relax a little. You’re talking to someone obviously less versed in this than you, and it won’t hurt you to field a few misinformed questions without acting like I’m personally insulting you with my wretched ignorance.
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I don’t find your ignorance wretched by any stretch, and on rereading, I agree that I wasn’t clear. I’m sorry for not communicating it better.
No, of course not. The only way to figure out what’s “proper” and what isn’t is to examine usage. I’m quite confident in saying that standard American English, at least, does not permit this combination (though given what Cat Jones said earlier, I wouldn’t even want to guess what other dialects permit with it, since clearly usage of used varies enormously.)
In fact, I can’t find any uses that seem grammatical to me involving “used to” and any modal auxiliary - though I’m not sure I remembered all of the modals, so I’m not certain that there isn’t some sort of exception. Which is yet another bit of evidence that it does behave something like a modal verb. Your example with will is a particularly good one, because there’s no semantic reason why it shouldn’t work - that is, the sentence works perfectly well (as far as I can see) in terms of meaning, so we can be pretty sure that the problem is a syntactic one.
But, in contrast with modal verbs, you can’t invert used and the subject of the sentence in forming a question. Take Maria can speak several languages. To form a question, modals (and other auxiliaries) switch places with the subject: Can Maria speak several languages? It’s called SAI (Subject-Auxiliary Inversion).
You can’t do that with used to. Maria used to throw the best parties. Attempting SAI yields something like *Used Maria to throw the best parties? or *Used to Maria throw the best parties? (Asterisks are used to mark ungrammatical constructions.) Instead, you have to add the dummy auxiliary do, as you have to with normal verbs: Did Maria used to throw the best parties?
Same goes with negation. The difference between auxiliaries (both modal and non-modal) and regular verbs is that auxiliaries can have the negative particle ‘not’ directly attached, following the auxiliary, whereas with a normal verb you again have to use the dummy auxiliary do. Take the following: Maria can solve differential equations. To form a negative sentence, you simply add not after the modal: Maria cannot solve differential equations. Whereas if you don’t have an auxiliary verb, you add the dummy. Maria solves differential equations in her sleep works great, but *Maria solves not differential equations in her sleep is not used in Modern English (though it’s familiar, as this used to be the way negation worked.) Instead you have to say Maria does not [or doesn’t] solve differential equations in her sleep.
So let’s try it with used to: Maria used to wake up at five every morning to practice the theremin. *Maria used not to wake up at five every morning to practice the theremin doesn’t work at all. Whereas ?Maria used to not wake up at five every morning to practice the theremin is somewhat acceptable to me, but intuitively I think that not is paired with the infinitive - the scope of the negation in that sentence doesn’t actually affect used to but rather wake up. It feels more like the also marginal sentence ?Maria wants to not go to the party, in which not is paired with the verb go. (Both of those are pretty questionable sentences, but they are things that people say, particularly in informal usage. The difference in meaning between doesn’t want to do something and wants to not do something is subtle but I think there is one.)
So in my dialect, I form the negative with do: Maria didn’t use to wake up at five every morning to practice the theremin. This is common, though clearly some speakers consider it a bit less grammatically acceptable.
The test with forming a question using SAI is quite clear, and it tells us that used to is not really an auxiliary verb at all. The test with negation is a bit murkier - and I think the fact that some speakers find didn’t use to somewhat unacceptable is indeed evidence that used to has at least some modal auxiliary-like qualities (remember that in standard English only one modal auxiliary can be used in a sentence). Your point that it doesn’t normally appear with other modal auxiliaries suggests the same thing. A point against it is that auxiliaries ordinarily have particular negative inflectional forms and normal verbs do not (won’t, shouldn’t, hasn’t, and so forth. Those forms are usually called “contractions” in English classes - and that is indeed their origin - but there are solid linguistic reasons to treat them as having evolved into special inflectional forms.) Used to doesn’t have one (though again, it apparently does in Irish English: usedn’t.)
At any rate, everything I’ve read uses negation and SAI as the tests for modal auxiliary verbs. Those are particularly important tests because they can tease out a verb’s syntactic properties, and syntactic theory therefore treats auxiliaries quite differently than other verbs as a result. In fact, “modal auxiliary verb” is properly defined as a class of verbs that have those particular syntactic properties. Those syntactic tests suggest that it’s not a modal auxiliary in standard American English. Clearly it is in some dialects, though. And it’s easily conceivable that it might one day become one in SAE. But while it appears to lurk somewhere around the border between modal auxiliary and ordinary verb, it’s still somewhere on the ordinary verb side at present.
