QUESTION: Does “used to” change forms?
ANSWER: Good question. I thought I was sure of the answer until recently when I had to acknowledge the conflicting explanations and examples of sources I trust. At this point, I can only outline my thoughts and then turn to you, my colleagues, for a more definitive answer.
Thankfully, there’s at least agreement about the form and use of used to in affirmative sentences. All sources explain that this structure refers to past habitual actions, and the same form is used for all subjects. (I used to feel more confident. She used to feel more confident. They used to feel more confident. Etc.) In addition, all sources agree that used to appears in questions and in negative sentences with far less frequency.
The confusion begins when we try to show how to form interrogative and negative sentences. Do we drop the -d and use only “use to”?
First, we need to identify what this verb form is. Both Biber (73) and Greenbaum (39) use the label marginal modal auxiliary. “Marginal” can either be a helpful or harmful term, depending your point of view. Perhaps it’s good to recognize variation in forms because this might allow us to agree to disagree. On the other hand, students seeking a black-and-write explanation may be disappointed if we remain in the gray.
If we include used to in our discussion of modal verbs, we may feel strongly that the form must remain the same. Just as we make no spelling changes to should (Should we talk more? We shouldn’t be so vague.), we might argue the need to follow suit when we use used to: Did you used to think that? They didn’t used to do that.
But do you see the difference? With used to we insert the auxiliary do in the question and the negative. The only other marginal modal auxiliary that does this is need to: (present) Do we need to talk more? – No, we don’t need to talk more. / (past) Did we need to take more time? – No, we didn’t need to do that. The problem with this comparison is that need to can show present and past tense: I need to do this. / I needed to do that. In contrast, used to is a structure that is limited to the past.
If we group used to more closely with semi-modals, then it becomes easier to accept the changes in form. After all, have to uses the forms had to and didn’t have to.
Part of the problem may be connected to register. Most sources agree that used to is most frequently used in conversation. Like other modal verbs in spoken English, there is reduction. (Have) got to becomes “gotta,” for example, and ought to becomes “otta.” Our ears also recognize “hafta” as have to and “shoulda” as should have. Have our ears grown so accustomed to “usta” that we no longer remember if the verb should be written as used to or use to?
Greenbaum explains that used to functions as both “an auxiliary and as a main verb with DO-support” (40). Used not to is listed as a British construction, while didn’t use(d) to is listed as being British and informal American English. However, note that the final (d) is listed as a variation. Biber and his team limit their examples of negative forms to used not to and didn’t used to. The Longman Dictionary of Contemporary English includes examples with Did you use to…? / used not to / didn’t use to.
Perhaps didn’t use to was never a part of prescriptive grammar, but it has become so common in everyday English (particularly American – although I see similarities on US- and UK-operated sites), and now it has become a standard pattern. Is the reason why a good number of online and offline sources teach didn’t use to/ Did you use to…? because descriptive grammar dominated at the discussion table?
I should make a final note that all sources agree on having no change in form when used to is part of an adjective (participial adjective) + preposition combination, as in I’m not used to heated arguments. (= not accustomed to) / You’ll get used to her way of teaching. (become accustomed to)
Please let me know your thoughts. Which forms do you teach of used to and why?
Biber D. et al. (2007). Longman grammar of spoken and written English. Essex: Pearson Education Limited.
Greenbaum S. and Quirk R. (1995). A student’s grammar of the English language. Essex: Longman Group UK Limited.
Longman Dictionary of Contemporary English. Retrieved from http://www.ldoceonline.com/dictionary/used-to