The English Modals

English has a set of eight lexemes, known as the MODALS, and they are will, can, may, must, ought, need, dare, shall. Each of these lexemes has either one or two inflectional forms.  Each has an ABORIGINAL form, namely will, can, may, must, ought, need, dare, shall.  Four of them, known as the FULL modals, have a further, TRANSPORTED form: would is the transported form of will, could of can, might of may, and should of shall.  The ones with only an aboriginal form are the DEFECTIVE modals.  In tabular form:

Modal                  Aboriginal form       Transported form

will                           will                          would
can                           can                          could
may                         may                         might
must                        must                        —-
ought                      ought                       —-
need                        need                         —-
dare                        dare                          —-
shall                       shall                          should

Note the typographical conventions.  Terms of art are introduced in upper case.  Think of this device as defining the term in question. The names of the lexemes themselves are written in bold italics, the various forms of those lexemes (i.e. the words) are in (unbold) italics.  And, looking ahead to  semantics, the meanings of these modalities are written in bold roman.  Thus will represents the meaning – whatever it is – of the lexeme will.

It is perhaps tempting – and certainly some writers have been thus tempted – to think of the modals as auxiliary verbs.  Better to resist the temptation. Modals have no V-ing form, no V-en form, and (crucially) no V-s form.  In this they are quite unlike the other English auxiliaries, have and do.  Where we find the full panoply of the verbal paradigm.  Thus:

Verb      Base     V-s     V-ed     V-en     V-ing
have     have     has      had       had       having
do          do         does    did        done     doing

And there is no justification for thinking of (e.g.) would as the V-ed form of will.  The V-ed form of any uncontentious verb can occur in a clause unaccompanied by any other verb form.  This does not hold for would, nor for any other form of a modal.  Modals are always accompanied by either the base form of a verb, or a phase-modified version of the same:

Grannie would often taunt the vicar  (taunt is the base form of the verb taunt)
Grannie will have been drunk for hours by now (phase-modified version of will be).

We thus follow Frank Palmer and others in treating the modals as belonging to their own paradigm, quite different to that of the English verb. The various forms of the modals are, we shall say, SECONDARY AUXILIARIES.  And doing the sums, there are twelve of them.

(As an aside, this is not quite the most exact appreciation.  When it comes to incorporating negation into the picture, it turns out that there are more modalities than our eight, and hence more secondary auxiliaries than our twelve, for there are also negative modalities.  Cannot, for instance, has to be treated as a modal in its own right.  But we will ignore negation for the moment).

N.B. The observed difference between secondary auxiliaries and verbs marks the most fundamental dichotomy amongst the finite clauses of English, which divided strictly into two classes.  There are those clauses which strongly contain a secondary auxiliary: these are clauses of the SECONDARY PATTERN.  And there are those clauses which do not: they are PRIMARY PATTERN clauses.  (Here ‘strongly’ means otherwise than in an embedded clause, so that each word occurs strongly in just one clause).

A clause is PARSED AS A SENTENCE when it encodes a complete message of its own.  We will speak of messages encoded in primary-pattern sentences as PRIMARY messages, and messages encoded in secondary-pattern sentences as SECONDARY messages.

Some examples to help fix the idea. Each of

Grannie shot the sheriff
Australians don’t like it up them
The cobra is very wary of Grannie nowadays
The President called for Grannie’s arrest
Rooney has made a fool of himself

is a primary-pattern sentence, encoding a primary message. And each of

We can start selling Grannie’s clothes right now
Grannie will be drunk before sundown
You must be Dr. Livingstone
Germany might have won the war

is a secondary-pattern sentence encoding a secondary message.  Learn to recognise them, and to think of secondary messages as utterly different from primary messages.

There is, of course, a lot more to say about the modals. You will find some of it in Dudman, “Towards a Theory of Predication for English” (1985a), which we recommend.