Auxiliary Verbs, en anglais

I can already see people running away from this post, terrified by its title. (This, of course, presumes that there are people coming to this site in the first place!) Grammar, perhaps because it is so awfully taught, if at all taught these days in school, tends to frighten people like no other subject save perhaps mathematics. This is a tragedy, for grammar is in fact quite beautiful and often very systematic, quite like mathematics. I'm going to focus on what may seem like a rather strange topic for now, but I will try to be clear (and will also use colors!) in order to convey a little bit of the ultimately systematic nature of this topic.

What is an auxiliary verb?

The word “auxiliary” usually means something supplemental, something additional, possibly accompanied by a sense of superfluousness. But let that not mislead us, for auxiliary verbs are by no means superfluous; indeed, their proper use is essential not merely to ensure that a verb is well-formed, but also to convey a whole host of additional meanings that are not present in the verb itself. (In this sense, the auxiliary verbs are much like the auxiliary corps of the Roman army: the Numidian light cavalry, Balearic slingers, Thracian archers and the like, whose specialized combat skills were absolutely essential to the success of the Roman legions.)

Before looking at particular languages, let's dive a little more deeply into this “whole host of additional meanings”. Every verb has a semantic core, a meaning that is somehow present in every single form of its use (except for idiomatic usages and the like, of course). But in addition to this core meaning of the verb, the most basic action that it can convey, there are a number of additional nuances that can be conveyed: the time when this action takes place; the status of the action, i.e., whether it’s only just begun or in progress or about to end; the likelihood of the action happening, and so on. I picked these three particular sets of nuances not because they are exhaustive, but because they have their own names in grammar: tense, aspect, and mood respectively. Every language on earth has some way or the other of conveying these three things, and they are usually intertwined in strange ways that seem entirely non-strange because they are utterly internalized by native speakers. For this reason, they're sometimes referred to collectively as tam.

One more idea remains, that of grammatical voice, but I will get to it later.

For now, though, let's look at the tam structure of English. This list here may seem strange, even wrong; if it strikes you so, I request you, gentle reader, to hold back your criticism just a little bit longer and to accept what I say at face value for now. (This is not to say that my descriptions are perfect; far from it!)

• t: English has two tenses, the non-past and the past.
• a: English can represent a wide range of aspects, but in addition to an unmarked aspect whose meaning depends on tense, there are two further aspects that are intimately connected to the verb, the perfect and the continuous/progressive. 
• m: English has at least two moods, the indicative and the subjunctive. Some include a third, the imperative. English can express all sorts of complex combinations of moods using additional modal verbs, which are also of interest to us here; what is normally considered the future tense in English is strictly speaking a modal verb.

The English verb system
Enough of this, let's see this system in operation! Let's take a verb, and see what forms we can generate. To celebrate the coming of spring, let's take a verb describing an activity that can finally be performed outdoors: swimming. All grammatical forms that convey this core semantic value can be constructed from one of three so-called principal parts: the infinitive (in this case, to swim), the preterite (here, swam), and the past participle (here, swum). Not all English verbs have three distinct principal parts; I picked this because it does. A fourth part, which is not principal because it can be produced fairly regularly from the infinitive, but which is important because of its frequency of occurrence, is the gerund (here, swimming).

[A minor note: the gerund is identical in form to the verbal noun, but they serve dramatically different purposes and must never be confused. Consider the difference between the gerund swimming in the sentence I am swimming and the verbal noun swimming in the sentence Swimming is fun. Here's a simple rule of thumb to differentiate between them: if you can substitute the infinitive in the place of the word without destroying the original meaning, it is the verbal noun. The first use of swimming is a gerund because I am swimming means something very different from I am to swim, whereas the second use of swimming has to be a verbal noun because both Swimming is fun and To swim is fun essentially mean the same thing.]

On its own, using just the principal parts, we can produce the following forms.

• Non-past tense, indicative mood: 
• I swim. 
• You swim. 
• He swims. 
• We swim. 
• They swim.
• Non-past tense, subjunctive mood: 
• (It is necessary that) … I swim. 
• … you swim. 
• … he swim. 
• … we swim. 
• … they swim.
• Past tense, indicative mood: 
• I swam. 
• You swam. 
• He swam. 
• We swam. 
• They swam.

A few things are already clear.

• First, English verbs show almost no conjugations at all. In the non-past indicative, the only change is the introduction of the -s in the third person singular.
• Second, the non-past indicative and subjunctive are almost identical, with the only difference being that the subjunctive does not add the -s.
• And finally, it is abundantly clear that the bare English verb is sadly incapable of conveying any further meaning whatsoever. It desperately needs to be assisted, to be supplemented, to be augmented by something else in order to produce any sort of nuanced meaning at all. 

Did someone just call for assistance? In march the auxiliaries!

The English auxiliaries

Loosely speaking, we can classify all English auxiliary verbs into two classes: modal and non-modal. 

• There are three major non-modal auxiliary verbs in English: to be, to have, and to do. Of these, to do is mostly used to deal with negation. Both to be and to have act as aspectual auxiliaries, allowing us to convey additional nuances connected to time and to status of completion. 
• The main non-modal auxiliaries, which convey additional nuances of meaning connected to likelihood and certainty, are shall / should, will / would, can / could, may / might, and must. 

The major difference between the modal auxiliaries on the one hand and the non-modal auxiliaries is that the latter also serve as full verbs in the language: to be means to exist, to have means to possess, and to do means to enact or to perform. The modal auxiliaries, on the other hand, are deficient; they have neither infinitives nor past participles. Another major difference between the modal and non-modal auxiliaries will soon become apparent. 

In order to distinguish between these different uses, I will represent all auxiliary verbs in dark green and all modal verbs in dark blue hereon.

Non-modal auxiliaries in English
So what is the structure of an auxiliary construction in English? It is always the auxiliary verb that is conjugated, while the main verb that is being augmented takes some sort of indeclinable form.

• With have, this form is the past participle, so that the form is to have + past participle
• With be, this is the gerund, so that the form is to be + gerund

I will represent this indeclinable part of the verb in bold.

Thus, in the plain sentence I swim, the verb to swim can give us the following auxiliary usages:

• With have (this is the so-called perfect aspect, since it communicates the completion of an action):
•  I have swum.
• I had swum.
• With be (this is the continuous-progressive aspect):
• I am swimming.
• I was swimming.

Our understanding of the structure of the auxiliary allows to generate yet another form, the so-called perfect progressive. This involves taking the verbal structure to be + gerund and treating its conjugating part (the verb to be) as the basis for generating the indeclinable portion of the verbal structure to have + past participle. This gives us

to have + past participle of to be + gerund,

or more simply

to have been + gerund,

where been is green to show that it came from the auxiliary be and bold to show that it is indeclinable. Thus, two forms of this construction:

• I have been swimming.
• I had been swimming.

Modal auxiliaries in English
The modal verbs in English are strange beings. They are highly deficient, lacking even the most basic accoutrements of regular verbs like the infinitive, the past participle, and the gerund. This, when combined with our knowledge of the non-modals have and be, tells us something:

English does not permit non-modal auxiliaries to be followed by a modal auxiliary.

So what is the structure of a modal auxiliary construction? As with the non-modal construction, this also involves one part that can conjugate (at least to the extent that English modal verbs conjugate) and one indeclinable part. The modal auxiliary construction is

modal verb + bare infinitive,

where what I mean by the “bare infinitive” is simply the infinitive minus the ‘to’ at the beginning.
This structure also immediately tells us another rule:

English does not permit modal auxiliaries to be followed by another modal auxiliary.

This is simply because modal verbs lack infinitives, so there is no way we can arrange them into this kind of structure. It’s also worth noting that this is not the case for non-modal auxiliaries; as we saw, we can indeed have the sequence to have been + gerund.

Anyway, let’s look at some examples. In properly prescribed English (not that this is followed any longer), the future tense is expressed in the first person using the modal shall and in the second and third persons using the modal will. So the two sentences I swim and He swims can be put into the future thus:

• I shall swim.
• He will swim.

If that’s all there were to modal auxiliaries, there wouldn’t be much to write home about. Things get interesting, though, because modal auxiliaries can be followed by non-modal auxiliaries. This is, of course, because the non-modal auxiliaries have and be do have bare infinitives. Thus, we can add considerable temporal nuance to our proclamations for the future thus:

• I shall swim. 
• I shall be swimming.
• I shall have swum.
• I shall have been swimming.

The Passive Voice
The auxiliaries we saw so far help expressed semantic nuances: nuances of meaning to do with time and likelihood. There is one more construction in English that uses an auxiliary verb, but this is largely for syntactic purposes: the passive voice. (This is not to say that the English passive voice is semantically identical to the English active voice; it is not.)

Slightly confusingly, the auxiliary verb for this is also to be; I will distinguish it from the non-modal auxiliary be by coloring this one dark red. The passive voice of a verb is formed thus:

to be + past participle,

and hence this must not be confused with the auxiliary construction using to have.


Examples, as always. The sentence Jack eats the fruit is in the active voice, and can be transformed into the passive voice as The fruit is eaten (by Jack). As before, the verb is here is a full-fledged verb, and can be put into all of the various combinations of modal and non-modal auxiliaries illustrated above as follows. It is worth noting, however, that some of the combinations do sound strange to the ear, even if they are technically permissible.

• The fruit is eaten.
• The fruit was eaten.
• The fruit is being eaten.
• The fruit was being eaten.
• The fruit has been eaten.
• The fruit had been eaten.
• The fruit has been being eaten. [This is a very weird construction, and I cannot recall seeing it anywhere. It would only make sense in a very limited semantic range, such as The fruit has been being eaten by Jack since 10 am this morning, but it has still not been eaten completely! And even here we would probably put the first clause in the active voice and say Jack has been eating the fruit since 10 am this morning, but it has still not been eaten completely!]
• The fruit had been being eaten. [Same caveat as above.]
• The fruit will be eaten.
• The fruit will be being eaten. [This too sounds a little weird to the ear.]
• The fruit will have been eaten.
• The fruit will have been being eaten. [This is perhaps even weirder than its non-modal counterpart, if that is even possible!]

For the future, auxiliary verbs in other languages.