Suppose someone asked me the question, "Have you completed the project?". A standard response would be "I have". Why does the equivalent "I've" sound so strange and never used as a replacement?

I am also trying to think of other responses where contractions are used as a complete sentence, but I can't think of something concrete.

Not sure if this even works, but for example, if I were to ask "I am going to pick you up after work", an accepted response could be "Don't. I'm already on my way home". Even if it isn't a complete sentence, it still sounds a lot cleaner than the "I've" response.

Is there a linguistical reason for this?

  • 1
    This is a straight-up syntax question about grammaticality.
    – user6726
    Aug 22, 2019 at 16:44
  • 10
    @user6726 I'd say it's on-topic, since the question isn't "is X grammatical?" but "why isn't X grammatical?". "Why" questions like this, to me, fall under linguistics rather than usage.
    – Draconis
    Aug 22, 2019 at 17:29
  • 1
    That's pretty much my point; I'm arguing against closing.
    – user6726
    Aug 22, 2019 at 18:20
  • 3
    Related question (with duplicate) on ELU also dealing with ‘shortest possible sentence’. Aug 23, 2019 at 9:06
  • 2
    Note that, as you suggest, there's nothing especially bad about "I've"; "are you going to pick me up?" "I'm"; "am I your favourite person?" "you're"; and "is he going to the show?" "he's" all sound as bizarre, at least to me.
    – LSpice
    Aug 23, 2019 at 19:10

4 Answers 4


English syntax makes a distinction between auxiliary verbs and full verbs. (Note that this answer is only talking about English; other languages do things differently. And as people have pointed out in the comments, specifically my Midwestern American dialect: British and Irish readers will probably disagree with several of my grammaticality judgements, since those dialects allow contractions in some places where AmE forbids them. See the comments for some examples!)

"Auxiliary" verbs have a few special properties in English; the most famous one is that they swap places with the subject when asking a direct question. For example, can is an auxiliary verb in the sentence he can swim, so if you turn it into a question, it moves to the front: can he swim? The verb likes seems similar on the surface, but is not an auxiliary: he likes to swim, but not *likes he to swim? Instead, an extra auxiliary is added for the question: does he like to swim?

Things get trickier when using verbs like "have", which can be either auxiliaries or full verbs, depending on their meaning. Compare you have finished ~ have you finished? against you have a cat ~ *have you a cat? In the first case, it's an auxiliary marking what linguists call "perfective aspect"; in the second case, it's a full verb indicating ownership. This is why do you have a cat? *I've is ungrammatical: only auxiliary verbs can contract.

And on top of that, there's an additional rule. Auxiliary verbs usually come attached to the full verb, but sometimes that full verb disappears if it's clear from context. This is called verbal ellipsis, and is extremely common: Have you finished? I have. Do you take this woman to be your wife? I do. But, crucially, auxiliary verbs cannot contract when there is verbal ellipsis. This is why your first example (have you completed the project? *I've) is ungrammatical.

These rules together can be summed up as: certain verbs in English can contract together with the preceding word, but only when acting as auxiliaries, and not if the following full verb is elided.

P.S. An extra point was added while I was writing!

Not sure if this even works, but for example, if I were to ask "I am going to pick you up after work", an accepted response could be "Don't. I'm already on my way home". Even if it isn't a complete sentence, it still sounds a lot cleaner than the "I've" response.

This is a different type of contraction. Another feature of auxiliaries in English is that they can be negated by putting "not" directly after them; full verbs can't do that without sounding extremely archaic (*he completed not the task!).

When this happens, the "not" can sometimes contract to "n't", losing its vowel. But this is separate from the auxiliary itself getting contracted, which is what was happening up above. "Not"-contraction isn't subject to the same restrictions, which is why I didn't is a valid sentence, but *I'dn't isn't.

P.P.S. If you look into this further on your own, be aware that there are two competing definitions of "auxiliary" in English! One definition, the one I'm using, is: auxiliary verbs are the ones that can swap places with the subject in negation ("syntactic auxiliaries"). Another definition is: auxiliary verbs are the ones that have no semantic meaning, only grammatical meaning ("semantic auxiliaries"). Some people use the term "modal verbs" for the second meaning, but that term can also have different definitions…welcome to the wonderful world of linguistics terminology!

This is mostly relevant because of the verb "to be": syntactically, it's an auxiliary ("is this a pigeon?" "this is not a pigeon"), but semantically, it's not ("I think, therefore I am"). For the purposes of this answer, I'm only using the syntactic definition, not the semantic one. But don't be surprised if you see other people do it the other way around.

  • 6
    @vectory I should clarify, this answer is only talking about English. Contractions in other languages work differently.
    – Draconis
    Aug 22, 2019 at 18:49
  • 2
    Also applies to modals (as in user6726's answer) and copulæ: "Are you ready?" "Yes, I'm." Aug 22, 2019 at 23:12
  • 8
    Re: your 4th para about OP's example where "I've" is ungrammatical. But your explanation incorrectly rules out "I've not" (at least for my English!) Aug 23, 2019 at 6:28
  • 7
    Note that have is often treated as an auxiliary in BrE and especially IrE, even when denoting possession. “Have you a cat?” is perfectly valid (if somewhat old-fashioned). “Have you any idea what…?” is normal enough even in AmE. The ‘additional rule’ (that auxiliaries can only contract if the main verb is elided) is what’s needed to account for the ungrammaticality of “*I’ve.”. Aug 23, 2019 at 8:57
  • 3
    @Draconis "Has everyone here received their goody bags?" "I've not!" sounds right to me in British English.
    – Muzer
    Aug 23, 2019 at 15:00

You can't delete a vowel and also stress it. That's obvious. So deleting a vowel prevents stressing it, and stressing a vowel prevents deleting it. A principle of English stress is that the last stressed vowel in the last word of a phrase bears the main stress in that phrase -- this is the Nuclear Stress Rule, or NSR.

Putting these two things together, we can predict that you can't delete the last stressed vowel in the last word of a phrase. In your example, answering the question "Have you completed the project?" with "I have completed the project" leaves the vowel of "have" in a vulnerable position for contraction, since "have" is not at the end of a phrase, and the NSR is inapplicable to its vowel. In the shortened answer "I have", however, the NSR requires stress on the vowel of "have", since it is at the end of its phrase (the sentence), thus preventing contraction.

  • 4
    Doesn't this account incorrectly rule out "Don't." (see end of question)?
    – TKR
    Aug 22, 2019 at 20:55
  • 6
    Yes, it does incorrectly rule out "Don't". One idea about that is that "don't" is not actually a contraction, synchronically, though etymologically, of course, it is a contraction. In McCawley's treatment", "n't" is treated as a morpheme distinct from "not", though of course this is an ad hoc adjustment.
    – Greg Lee
    Aug 22, 2019 at 23:21
  • 4
    Not completely ad hoc in my opinion, because n't behaves different from not in another important way too: don't you think so? (*do not you think so?). I can't see how this usage is either synchronically or diachronically a contraction of do not, although I assume I could easily be surprised about the diachronically.
    – LjL
    Aug 22, 2019 at 23:35
  • 1
    @LjL, then also there's the pronunciation /downt/ rather than */duwnt/.
    – Greg Lee
    Aug 22, 2019 at 23:43
  • 1
    I should point out that some of the reasoning in my answer is idiosyncratic. In a multistratal theory, in which there are several meaningful levels of structure, such as transformational grammar and generative phonology, it is possible to both stress a vowel and delete it. In fact, it is straightforward. First you stress the vowel, then you delete it -- no prob. Also, it is not the case, in such theories, that deleting a vowel by contraction, robs the NSR of a chance to apply -- it would simply apply (incorrectly) to a different vowel.
    – Greg Lee
    Aug 25, 2019 at 18:40

There are multiple technical explanations, depending on theoretical framework, but one non-technical way to look at it is that you have to include an "actual verb" in the response, where the verb is "stressed" (emphasized, put in focus). You can't say "*I'll", but you can say "I will"; you can also say "I'll go", "I won't, so it's not that you can't do contractions in such responses. One popular analysis is that contraction involves a morphosyntactic process of cliticization, where an apparent full word can also be realized as a phrasal affix on some preceding word. Despite appearances, "*I'd; *I'll" doesn't have a verb. But "I would" does.

There is more to it than that, since you can't say "*I'd have" (as in "I would have gone"). This has to do with the stress requirement (which is about semantics – what you are focusing on). Notice that there is a subtle difference between (1) "I would have sold it" and (2) "I would have sold it", and that (3) "I would have sold it" is kind of bizarre. (1) focuses on the fact that you did not actually sell it and suggests there are other reasons for not selling it; (2) focuses on the choice of selling versus some other action. I cannot conjure up any sensible thing that you'd be contrasting in emphasizing "have" in 3.

  • About the second paragraph, one contraction I could see myself using, although it's not very standard, is "I would've".
    – LjL
    Aug 22, 2019 at 18:05
  • I'd say "woulda" (no [v]). The have / of / ə problem of "have" is complicated.
    – user6726
    Aug 22, 2019 at 18:20
  • Ayə, it's complicated?
    – vectory
    Aug 23, 2019 at 5:09
  • I prefer this to the accepted answer. Examples of “I’ve” referring to possession of a thing (effectively replaceable by either “I have” or “I’ve got”), while not very common, seem grammatical in other contexts: “I’ve a million things to do,” “I’ve a great regard for you,” Melville even has one, “I’ve a good mind to go find him.” The real problem strikes me as having something to do with the fact that the sentence buries its lede.
    – CR Drost
    Aug 23, 2019 at 21:15
  • @CRDrost I think the accepted answer (Draconis's) is very similar to this one; they're both talking about restrictions on auxilliary verbs (this answer treats auxiliary verbs and their contracted forms as being Different Things with different allowed environment; Draconis's treats them as the Same Thing but with the contraction being restricted in some ellipses).
    – awe lotta
    Jun 10, 2023 at 4:38

I'll give a minority opinion to be subsumed under the other so far uncontestable answers.

Your premisses is flawed:

  • Overwhelmingly, the shortest response to "have you" would be "Yes!", and who knows, maybe that's a contraction?

The word gese (with g pronounced as y) has existed since the days of Old English. [...] The s-part remains in limbo. It may be the stump of swa “so” or of sie, the present subjunctive of the Old English verb to be. [Anatoli Liberman, Etymology of affirmations: yes, yea, yeah, yep, aye]

  • "Have you?" is subjunctive mood. English doesn't inflect for subjunctive and Have your homework done by tomorrow! is rather analyzed as imperative. "Have done" shows the present-perfect aspect in "have" and the past tense in "done". Effectively, I suggest "Have you completeded?" is often met with "I did", analoguous to "Have you done it?", "I did". "I have" would seem a little stilted in contrast, like a father addressed "sir", which is nevertheless a thing, but in a context that is perhaps less amenable to contractions. did does not contract well because I'd say it'd be morphemically and phonologically underspecified. In the same sense I've would be underspecified,perhaps, in the sense @user explained. I'd say "I did [it, and if you want me to I'll explain in meticulous detail how it went]!". You don't say "I have [it]", but rather suggest "I have [done]", the short form (simple past, preterite, call it what you will).

As a L2 speaker the difference between have and did perfectives is not quite obvious.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.