"I must / have to call her." "No, you don't have to."

[jutfrank]

By the way, a little off-topic, is there any difference in meaning between "You need not to worry" and "You need to not worry" (from #9)?
(I understand that "You don't need to worry" is a completely different idea by analogy with "I didn't have to do it" and "I had not to do it")

Get clearly in mind the distinction between zero necessity and negative necessity. When the negator not comes after the verb need, it reverses the polarity of the necessity:

You need to worry. = [positive necessity]
You need to not worry. = [negative necessity]

In the latter sentence, not operates on the verb worry. Compare that to:

You don't need to worry. = [zero necessity]

Here, it operates on the auxiliary do, so it doesn't reverse the polarity, it nullifies it.

Have I understood your question?


Another related and interesting point here concerns the chunk needn't as used as an auxiliary verb to express zero necessity. This is best shown in the context of past necessity. Look at this:

a) I needn't have woken up early. = It was not necessary for me to wake up early.

Now compare this to a similar sentence using didn't need, which also expresses zero necessity but has what we call a difference in implicature (a kind of meaning):

b) I didn't need to wake up early. = It was not necessary for me to wake up early.

On the surface, the meaning is the same (semantics). However, the implication (pragmatics) is quite different, being thus:

a) I needn't have woken up early. = I did wake up early, despite it not being necessary.
b) I didn't need to wake up early. = I did not wake up early because it was not necessary.

 

[Michaelll]

On the surface, the meaning is the same (semantics). However, the implication (pragmatics) is quite different, being thus:

a) I needn't have woken up early. = I did wake up early, despite it not being necessary.
b) I didn't need to wake up early. = I did not wake up early because it was not necessary.

Yes, I understand that the difference between "He needn't have done something" and "He didn't need to do something" is that the first means he did it, but now we know that it was not necessary while the second doesn't tell us whether he did it or not, but only that it was not necessary for him to do it.

Is that what you're asking?

It was very interesting, especially the last part. But I'm not sure yet if you understood my question I managed to explain my question.

"You need not to worry" simply means "You needn't worry" which in the present has the same meaning as "You don't need to worry".
"You need to not worry" means ... well ... this is what it means "You need to not worry" (I didn't come up with a better way of explaining).
Do I understand this correctly?

By analogy with written above, if we're talking about 'have to' in the past, would it have to be "I had to not do it", or would "I had not to do it" work as well?

(just to say, I understand that "I didn't have to do it" is a completely different idea)

 

[Michaelll]

You need to worry. = [positive necessity]
You need to not worry. = [negative necessity]

In the latter sentence, not operates on the verb worry. Compare that to:

You don't need to worry. = [zero necessity]

Here, it operates on the auxiliary do, so it doesn't reverse the polarity, it nullifies it.

Have I understood your question?

Now, that you've edited your reply, I see, yes, you have understood my question. Thank you!

The only thing: do we have to put it in this word order "You need to not worry" or is this "You need not to worry" fine as well?

In other words:

• You needed to worry. [positive necessity]
• You didn't need to worry. [zero necessity]
• You needed to not worry. [negative necessity]
• You needed not to worry. [?] Would this work as a negative necessity?

• I had to do it. [positive obligation]
• I didn't have to do it. [zero obligation]
• I had to not do it. [negative obligation]
• I had not to do it. [?] Would this work as a negative obligation?

 

[jutfrank]

Sorry, it took a long time to edit my post. I misunderstood at first, but then I caught on after I'd posted.

The only thing: do we have to put it in this word order "You need to not worry" or is this "You need not to worry" fine as well?

They're essentially the same and both fine. You can also say You need not worry. However, I think there is some kind of question to be found about a difference between each of these forms, but I'm not sure we need to go down that rabbit hole.

• I had to not do it. [negative obligation]
• I had not to do it. [?] Would this work as a negative obligation?

Good question. A part of me wants to say yes, but I'm sure I'd be in a very small minority, because it's so unnatural that most people would say it's wrong. So I'll say no.

The semi-auxiliary obligation phrase have to really can't be separated like that—the have and the to parts must stay together. I imagine you can probably find some examples of old-fashioned use where they are separated, though. With need to and ought to and dare to, each of which are also auxiliary-like, there are no such limitations on this separation.

 

[Michaelll]

You can also say You need not worry.

Isn't "You need not worry" the full form of "You needn't worry" which expresses the zero necessity?
I, in turn, was asking about the negative necessity.

You need to worry. = [positive necessity]
You need to not worry. = [negative necessity]
You don't need to worry. = [zero necessity]

The semi-auxiliary obligation phrase have to really can't be separated like that—the have and the to parts must stay together. I imagine you can probably find some examples of old-fashioned use where they are separated, though. With need to and ought to and dare to, each of which are also auxiliary-like, there are no such limitations on this separation.

Got it! Thank you! So, if I want to show the 'negative obligation'(must not) in the past I should use this word order "I had to not do something".
As for the whole phrase in the negative necessity, will native speakers understand me in spoken English? Is that natural?

(for myself)
in the present/future

• I have to do something. / I must do something. [positive obligation]
• I must not do something. / I have to not do something. (?) [negative obligation]
• I don't have to do something. [zero obligation]
  -
• You need to do something. [positive necessity]
• You need to not do something. [negative necessity]
• You don't need to do something. [zero necessity]
• You needn't do something. [zero necessity X2]

in the past

• I had to do something. [positive obligation]
• I had to not do something. [negative obligation]
• I didn't have to do something. [zero obligation]
  -
• You needed to do something. [positive necessity]
• You needed to not do something. [negative necessity]
• You didn't need to do something. [zero necessity]
• You needn't have done something. [zero necessity but implies you did it]

 

[jutfrank]

Isn't "You need not worry" the full form of "You needn't worry" which expresses the zero necessity?
I, in turn, was asking about the negative necessity.

Yes, that's right. You need not worry expresses zero necessity, not negative necessity. I mentioned it because we were talking about form.

So, if I want to show the 'negative obligation'(must not) in the past I should use this word order "I had to not do something".

Yes.

As for the whole phrase in the negative necessity, will native speakers understand me in spoken English? Is that natural?

(for myself)
in the present/future

• I have to do something. / I must do something. [positive obligation]
• I must not do something. / I have to not do something. (?) [negative obligation]
• I don't have to do something. [zero obligation]
  -
• You need to do something. [positive necessity]
• You need to not do something. [negative necessity]
• You don't need to do something. [zero necessity]
• You needn't do something. [zero necessity X2]

in the past

• I had to do something. [positive obligation]
• I had to not do something. [negative obligation]
• I didn't have to do something. [zero obligation]
  -
• You needed to do something. [positive necessity]
• You needed to not do something. [negative necessity]
• You didn't need to do something. [zero necessity]
• You needn't have done something. [zero necessity but implies you did it]

All good.

 

[Michaelll]

All good.

This thread has taught me a lot of what I've been trying to understand for quite a while, thanks to your help. Thank you very much.