Modal Verbs

Modal verb is any of a subgroup of auxiliary verbs that express mood. Modal verb share some distinct characteristics that grammatically differentiate them for other verbs, which are:
- They have no-s form, infinitives or participle
- They do not have the set of tenses formed with be or have which most verbs have
- They form question by inversion and negative by adding not or-n’t; and
- They must be used as auxiliary to lexical verbs.
English contains five modal auxiliary, all but one of which occur in a present and past tense form, which are :
- Can – Could
- May – might
- Shall – Should
- Will – Would
- Must
There’s no present tense form of must in Modern English, although the form must filled that role as late as Middle English and occurs in German. The term tense simply refers to the form of adverb not necessarily to its time reference.
E.g : Might also can used explain future time.
“Claudia might be swear her promise to me”
Marginal Modal Auxiliary
The common marginal modal auxiliaries are used to, ought to, dare and need. But here I only describe two of them which are ought to and used to.
- Marginal modal auxiliary used to always take the to-infinitive and occurs only in the past tense.
Jane used to visit her grandmother twice a week
So it means in the past Jane always visit her grandmother twice in a week, but now he didn’t.
- Ought to normally has to-infinitive, but the to is optional following ought in ellipsis :
a. You ought to be more diligent than before
b. Ought I to be more diligent than before?
Modal idioms and semi-auxiliaries
Two other categories of verbs are intermediate between auxiliaries and main verbs. They express modal or aspectual meaning.
a. The modal idioms
The modal idiom is combination of auxiliary and infinitive or adverbs. None of them have non-finite forms and they are therefore always the first verb in the verb phrase. The common modal idioms are had better, would rather, have got to and be to.
b. Semi-auxiliaries
Semi-auxiliary is a set of verb idioms which are introduced by one of the primary verb have and be. They have non-finite forms and can therefore occur in combination with preceding auxiliaries. The common semi-auxiliary verbs are be able to, be about to, be bound to, be likely to, be going to, be supposed to, have to.

In other books described there are two kinds of modal, first are basic modals and second is phrasal modal . The basic modal contains : can-could, shall-should, may-might, will-would, must, ought (to) and had better. Then, the phrasal modal contains: be able to, be going to, be supposed to, have to, have got to and used to.
For the practical purposes, the meanings of the modals are often differentiated into Dynamic, Epistemic and Deontic.
1. Dynamic modal
A modal verb that “predicate something”. Dynamic modals make factual statement.
E.g : I can type my homework tonight.
2. Deontic modal
A modal verb that intended to impose an obligation or grant permission or otherwise influence behaviour
- You must listen what your parent speak
It’s such a behaviour that happens in every single people that every people must listen their parents.
- You may borrow my pen
This means may intend express people told to another people that he can borrow his pen (grant permission)
- You shouldn’t do that!
Shouldn’t express that to impose an obligation
3. Epistemic modal
Epistemic modal concerned with like hood or degree of certainty of something. Epistemic sometimes it called extrinsic modality