Do auxiliary verbs always serve to express a mood or aspect that is different from simple indicative (or a tense)? Or are there cases where a sentence is in simple-indicative-present with the presence of an auxiliary verb?

  • We don't use the term "indicative" since it does no work. We talk of "declarative" clauses which may contain an auxiliary verb: 'She can swim' and 'Ed is a teacher' and so forth. Auxiliary verbs are verbs with the NICE properties, not verbs that help other verbs: you couldn’t identify them by asking whether or not they help the following verb. They are called auxiliary verbs because they characteristically express meanings similar to those expressed (either in the same language or in other languages) by verb inflection.
    – BillJ
    Commented Sep 17, 2016 at 14:08
  • @BillJ Why does indicative "not work"? Commented Sep 19, 2016 at 18:48

5 Answers 5


No, the use of auxiliaries is not directly linked to aspect, mood or tense in the first place. This may be so in some or many cases by coincidence when morphological or syntactic marking is not available, but the link between auxiliary verbs and TAM is not a logical necessity.

On the one hand, there are (even in English) cases where the use of auxiliaries does not change aspect/mood/tense:

  • They charged him --> He WAS charged (change to passive voice, but not indicative or tense)
  • You realize --> You DOn't realize (negation, same tense and mood)
  • He responds --> DOES he respond? (qustion formation, grammatical change but not about mood, tense or aspect)
  • I think --> I DO think (enforcement, no kind of grammatical change)

On the other hand, there are numerous cases where TAM is expressed other than by an auxiliary verb:

  • I play --> I playED (morphological marking of tense)
  • You wash the dishes --> Wash the dishes (imperative mood by syntactic marking)
  • French: Tu pars --> Je veux que tu PARTES (subjunctive mood)
  • langauges with evidentiality, apectual, ... affixes

And there are even cases where an auxiliary is used for indicative present, namely present progressive (if you take this as the "normal" present) in English:

  • Mary IS cooking

So the answer is no, auxiliaries do not always express TAM differing from "simple indicative present", not even necessarily grammatical features.

  • Thanks for the answer. As for your last remark, does that not depend on the set of features you consider? One could define Voice, Polarity and even "Enforcement" as extra features and extend my question that way. Commented Sep 20, 2016 at 8:22
  • @Wouter Lievens You question only mentions tense - aspect - mood to which these extra features don't belong. If you want to extend it to grammatical features, voice would belong there too, yes. But I don't really see where semantic enforcement could fit in; this is not a grammatical, but a rather semantic feature, and if you want to include that too, then you could include basically everything that auxiliaries could be used for, which makes the question a bit redundant. I.m.o., the insight that auxiliaries are not used solely for grammatical features is the most important one for the question. Commented Sep 20, 2016 at 9:35
  • In principle you are of course right. You can keep coming up with (semantic) features to differentiate everything. However, as I posted in another comment, it's a lot harder to invent a grammatical feature that distinguishes "I work today" from "I walk today" than the examples you listed. Commented Sep 20, 2016 at 10:07
  • @Wouter Lievens I don't really understand your point. Isn't the do example exactly what is desired? Commented Sep 21, 2016 at 21:23
  • It's hard to explain what I really meant so my question isn't well states. Your (and some other) examples did offer me insights and that's what I was after. Commented Sep 22, 2016 at 17:17

No, auxiliary verbs don't always express something other than simple indicative. Yes, there are cases where a sentence with an auxiliary verb is in the simple indicative. For instance, "Hal is a fisherman." The "is" is an auxiliary verb, since it inverts with the subject in the corresponding yes-no question "Is Hal a fisherman?", and it is a simple indicative.

  • It seems my definition of auxiliary verb is off. I was strictly referring to cases where the auxiliary verb exists in addition to the main verb (as in "I will sleep"). Commented Sep 16, 2016 at 8:50
  • 2
    You are not alone in admitting as auxiliaries only those verbs which accompany a main verb. Indeed, that view is built into the very term "auxiliary". The trouble with that is there is no evidence that it's true about English. Beginning with Chomsky's Syntactic Structures, linguists have made auxiliary status independent of whether there is a main non-auxiliary verb present. Our analysis of a language ought to be based on facts about that language, not facts about traditional terminology.
    – Greg Lee
    Commented Sep 16, 2016 at 10:13
  • I understand that. I'm not an academically trained linguist, just a software engineer with a passing interest in grammar. Naturally evolved concepts just don't lend themselves well to strict categorization. Commented Sep 16, 2016 at 12:58
  • Right. And strict categorization has little use for describing naturally evolved phenomena. Which is why Greg's answer is right, for any grammatical use of "auxiliary verb"; grammatical terms are determined by form and not meaning. If you call be an auxiliary when used for the Progressive or Passive construction (a neutral term), then you should call it an auxiliary when used for the Predicate Adjective or Predicate Noun construction. The forms are identical and so are the usages; if you don't call it an auxiliary because it's the only tense-carrying verb, you're assuming the consequent.
    – jlawler
    Commented Sep 20, 2016 at 13:24

A German counter-example is Er wird geschlagen where the auxilliary werden expresses the passive voice, but is clearly simple-indicative-present.

  • 1
    Excellent example, thanks. So auxiliaries can also express a change in voice. I guess that broadens my question: do auxliaries that support a main verb always modify some grammatical feature? Commented Sep 16, 2016 at 9:56
  • 1
    @WouterLievens: Define "some grammatical feature". There is always a reason for using an auxiliary verb. What about negation in English: He doesn't like it.? Is ngation "some grammatical feature"? Commented Sep 16, 2016 at 10:11
  • In my view yes, it's the polarity of a sentence. I'll illustrate further: "I work here" and "I live here" have all the same grammatical features. No difference in tense, mode, aspect, voice, polarity, etc. My question is therefore is it possible to construct a sentence like "I <X> <work> here" where <X> is an auxiliary and <work> is some conjugation of "to work", with no difference in grammatical features. I realize that's a contrived question that probably works only in my head. Commented Sep 16, 2016 at 13:00
  • @Wouter Lievens: "I do work here"?
    – mobileink
    Commented Sep 19, 2016 at 3:12

No, e.g. in Czech, the past tense is expressed by the copula verb "být" (to be) and the past participle of the main verb. It is the main verb that expresses the aspect (perfective/imperfective).

Dělal jsem - I did / I was doing (imperfective aspect)

Udělal jsem - I did / I have done (perfective aspect)

On the other hand, the mood is expressed on the auxiliary

Dělal jsem - I did

Býval bych dělal - I would have done

So this is language dependent and structure dependent.

E.g. in Czech it is currently impossible for the verb "být" to take over the aspectual function in the past tense as this is one of the few verbs that do not distinguish perfective/imperfective aspects. On the other hand in the future tense, the imperfective verbs form future with synthetic future tense of "být" + infinitive of the main verb, while for perfective verbs, the future is expressed merely by their "morphological present", since there is nothing like perfective present tense:

Dělám - I do / I am doing (imperfective aspect, present tense)

Udělám - I will do / I am going to do (perfective aspect, future tense expressed by "morphological present")

Budu dělat - I will do / I will be doing (imperfective aspect, future tense)

So here, the aspect is kind of expressed by the presence of the auxiliary (if not on the auxiliary, again the copula verb does not distinguish the aspect) - this can be seen with verbs that normally do not distinguish aspect (typically verbs of latin origin)

Informuji - I inform / I am informing (imperfective, present)

Informuji - I will inform (perfective, future - expressed by "morphological present)

Budu informovat - I will inform / I will be informing (imperfective, future)


In Portuguese, there are at least two different kinds of auxiliary verbs.

First, there are syntactical auxiliaries, that change grammatical features of the main verb. Those are ir (to go), ser (to be), estar (to be, too, but the meaning is quite different from "ser"), ter (to have), and haver (to have, but in different contexts - and, no, it is not a cognate of "have"; their similarity is a mere coincidence).

Ser is used for changing voice, not tense or aspect:

Joana processou José. - Jane sued Joseph.

José foi processado por Joana. - Joseph was sued by Jane. (foi is the past simple of ser.)

The others are used for tense/aspect modification. Ir + infinitive of the main verb indicates future or conditional, estar + gerundive of the main verb expresses "imperfect" (or continuous) aspect, ter and haver + past participle of the main verb express perfect aspect:

Eu vou dormir. - I am going to sleep. (Vou is the indicative present of ir.)

Eu ia dormir. - I was going to sleep.

Eu estou brincando. - I am joking.

Eu havia dormido. - I had slept.

Eu tenho dormido. - I have been sleeping.

Those verbs can also be used as main verbs on their own, with perhaps the exception of haver, whose present indicative, , seems to be evolving into some kind of particle - to the point that there is generalised confusion with the homophone preposition a.

Second, there are "modal" auxiliaries that change the semantics of sentences, such as querer (to want), poder (can), precisar (to need), parecer (to seem), without messing with tense or aspect (unless they are themselves flexed for tense/aspect).

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