Can I use this both forms interchangeably:

  1. People who didn't use to (such abbreviations)...
  2. People who are not used to (such abbreviations)...

I don't really feel /see the difference between these forms. For me the first sentence would be more natural, but in the text I was reading, the second form was used and it drew my attention.

What would be the difference between them?


  • 2
    Your first example in ungrammatical English. See this post at our sister site ELU. Jul 2 '17 at 9:50
  • 1
    @P.E.Dant, ok thanks, but this post doesn't actually answer my question. I'm not asking about the difference between didn't use to vs didn't used to.
    – Marcel
    Jul 2 '17 at 11:02
  • I left this out of my explanation; there are actually three forms: to be used to [doing something]; I used to [do something], a defective form; and to use. People who didn't use to tell lies, shouldn't start now. So, your 1) is OK but is not the same form as two.
    – Lambie
    Jul 3 '17 at 14:57
  • @Lambie His 1st is wrong since there isn't a verb after didn't use to Jul 4 '17 at 6:19

The expression is "be used to*".

If you are used to something, you are accustomed to it – you don’t find it unusual. If you get used to something or you are getting used to something you are becoming accustomed to it – it was strange, now it’s not so strange. (LearnEnglish - British Council)

Both ‘be used to’ and ‘get used to’ are followed by a noun (or pronoun) or the gerund – the ‘ing’ form of a verb

This concerns your second example, which is correct and appropriate:

  • People who are not used to such abbreviations. (Correct)

The first sentence is incorrect grammatically since "didn't use to" is applied incorrectly in the sentence.

We use ‘used to’ to talk about things that happened in the past – actions or states – that no longer happen now.

The negative is ‘didn’t use to’ and questions are formed with ‘Did you use to …?

  • People who didn't use to such abbreviations. (Incorrect)
  • People who didn't use to understand such abbreviations. (Correct)
  • The negative form of "used to" is contentious. So citation is needed for the latter part. Following Garner, I would say it should didn't used to.
    – user178049
    Jul 2 '17 at 17:38
  • @user178049 Didn't used to is incorrect, the didn't use to is simply the past negative of the past used to. Jul 2 '17 at 17:53
  • I didn't say it was correct, and I didn't say it was wrong either. I'm just prompting you to add a citation because this issue is contentious and opinions may vary.
    – user178049
    Jul 2 '17 at 17:55
  • @user178049 Btw, I can't see why you say that the negative form of used to is contentious! Jul 4 '17 at 6:46
  • At first, I, too, thought it should be "didn't use to." But after reading this post, I'm dubious. As Javalatte said, 'opinions vary'.
    – user178049
    Jul 4 '17 at 6:51

The idiom is: to be used to something.

Present: People who aren't used [or are not used to] to wearing green [etc.]

Simple Past: People who were weren't [or were not used] to wearing green [etc.]

PP: People who haven't been used to [or have not been used to] wearing green [etc.]

Often, English language learners confuse to be used to something with the verb to use something and the defective imperfect form: I used to [do something].

The form didn't use is the simple past tense of the verb use and is not related to the idiom given at the beginning of this answer. The verb use works like this in the SP:

He didn't use the paper I left on top of the printer.

The form of I used to [do something]. I used to play tennis=defective imperfect tense. Negative*: I didn't use to play tennis, the negative is not so common.

For repeat actions in the past.

  • There is the negative form "didn't use to" of "used to" (past actions and states). Consider: "He didn't use to play with her a lot when they were kids" Jul 2 '17 at 16:46
  • @SovereignSun One cannot cover every single thing under the sun. I was not commenting on "personal pronoun + used to". As in: I used to play football. That is another thing. And not the confusion of the asker.
    – Lambie
    Jul 3 '17 at 14:55

Just to sum up:

I mixed not 2 but actually 3 different forms up:


  1. regular verb use

1.1. He used the paper I left on top of the printer.

1.2. NEG: He didn't use the paper I left on top of the printer.


  1. idiomatic expression be/ get used to

2.1. People who are used to such abbreviations

2.2. NEG: People who are not used to such abbreviations.

and THIRD the most confusing:

  1. defective verb used to

3.1. I used to smoke, but now I've stopped.


3.2. I used to not like opera, but now I do.

3.3. I didn't use to like opera, but now I do./ I didn't use to drive a big car.

3.4. I use(d)n't to like opera, but now I do.

My example was:

4.1. People who didn't use to such abbreviations


4.2. People who didn't use such abbreviations. (AS: He didn't use the paper I left on top of the printer.)

and I wanted to use the sentence 4.1 with the meaning 3.3 but as I was pointed out it was incorrect. Now I understand why :)

  • 1
    You're welcome, however, please delete your answer as it isn't an answer or edit it so that it becomes an answer of your own. Jul 3 '17 at 9:49
  • 1
    @SovereignSun There's nothing wrong with an author writing an answer to their own question to explain what they know in their own words. I think explaining it from a different perspective is valuable. It should be written as an answer though, and not as part of a conversation. I've fixed it up a little bit for you Marcel. Feel free to change my edits.
    – ColleenV
    Jul 3 '17 at 17:25

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