Contents introduction chapter I grammatical meaning, grammatical form

The actuality of theme. The theme of my course paper is "Modal verbs and their functions in the English language". While examining this theme, we faced not only many different problems in finding exact materials related to this theme but also lots of new information, as a specific role and their characteristics of modal auxiliary verbs in Modern English, how it used to be and how it is used in our speech, nowadays.
The actuality of this theme is that modal verbs, known as "helping verbs" also, form one of the basic foundations of English grammar. We want to draw your attention to our theme, since it still needs further investigation on it; we tried our best to give the gist of this theme.
The object matter of the paper is modal auxiliary verbs and their characteristic features in the English language.
The aim and tasks of the paper. To study the functions of modal verbs in the English language is the aim of the work. According to this aim the following tasks have been put forward:

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  To study characteristic features of the modal verbs in the English language
  
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  To study primary and secondary functions of modal verbs
  
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  To study the usage of modal verbs in expressing obligation and necessity
  
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  To study principle modal verbs and their definition
  

The theoretical and practical value of the course work is that it can be used at the lessons as "Communicative grammar". Besides, the students of English department can use materials of this work for their presentations on subject "Modal auxiliary verbs"
The basic source of the paper. Azar B.S "Understanding and using English grammar", Palmer F.R. "Mood and Modality", Anthony W.R."English Auxiliaries"
The structure of the course paper. This course paper consists of introduction, four paragraphs, conclusion and list of literature.
Chapter I Grammatical meaning, grammatical form
1. General characteristics of modal verbs.
Verbs like can and may are called modal verbs. We use modals, when we are concerned with our relationship with someone else. We may ask for permission to do something, give or receive advice, make or respond to requests and offers. We can express different levels of politeness both by the forms we choose and the way we say things. Using modals in oral language is more kindly and persuasive than the most complicated utterance. And they can be used for various different purposes. Modal verbs are not used independently in the English language; they follow main verbs to give extra sense. Modal verbs generally express speakers' attitudes. Each modal has more than one meaning or use. Modal verbs are called defective because all of them (except dare and need) lack verbal and analytical forms (i. e. compound tenses, analytical of subjunctive mood, the passive voice). They are verbs because they can combine with a subject:

1. 
   They can sing
   
2. 
   He may arrive tomorrow
   
3. 
   I must have lost my presence of mind
   
4. 
   The children can sing
   
5. 
   James may arrive tomorrow
   

The modals can and could Old English can(n) and cuJd, which were respectively present and preterit forms of the verb cunnan ("to be able"). The silent in the spelling of could results from analogy with would and should.¹ Similarly, may and might are from Old English mseg and meahte, respectively present and preterit forms of magan ("may, to be able"); shall and should are from sceal and sceolde, respectively present and preterit forms of sculan ("to owe, be
Calmer, F. R., Mood and Modality, Cambridge Univ. Press, second edition, 2001, p. 33.
obliged"); and will and would are from wille and wolde, respectively present and preterit forms of willan ("to wish, want").
The aforementioned Old English verbs cunnan, magan, sculan and willan followed the preterit-present paradigm (or in the case of willan, a similar but irregular paradigm), which explains the absence of the ending -s in the third person on the present forms can, may, shall and will. (The original Old English forms given above were first and third person singular forms; their descendant forms became generalized to all persons and numbers.)
The verb must comes from Old English moste, part of the verb motan ("to be able to, be obliged to"). This was another preterit-present verb, of which moste the preterite was in fact (the present form mot gave rise to mote, which was used as a modal verb in Early Modern English; but must has now lost its past connotations and has replaced mote). Similarly, ought was originally a past form - it derives fromahte, preterit ofagan("to own"), another Old English preterit-present verb, whose present tense form ah has given the modern (regular) verb owe (and ought was formerly used as a past tense of owe).
The verb dare also originates from a preterit-present verb, durran ("to dare"), specifically its present tense dear(r), although in its non-modal uses in Modern English it is conjugated regularly.² However, need comes from the regular Old English verb neodian (meaning "to be necessary") - the alternative third person form need (in place of needs), which has become the norm in modal uses, became common in the 16th century.
A modal verb serves as an auxiliary to another verb, which appears in infinitive form (the bare infinitive, or the to-infinitive in the cases of ought and used as discussed above). Examples: You must escape; this may be difficult.^3
2 A Linguistic Study of the English Verb, Longmans, 1965, p. 46.
³ Warner, Anthony R., English Auxiliaries, Cambridge Univ. Press, 1993, p.58.
The verb governed by the modal may be another auxiliary (necessarily one that can appear in infinitive form - this includes be and have, but not another modal, except in the non-standard cases described below under Double modals). Hence a modal may introduce a chain (technically catena) of verb forms, in which the other auxiliaries express properties such as aspect and voice, as in He must have been given a new job.
Modals can appear in tag questions and other elliptical sentences without the governed verb being expressed: ...can he?; I mustn't.; Would they?
Like other auxiliaries, modal verbs are negated by the addition of the word not after them. (The modification of meaning may not always correspond to simple negation, as in the case of must not.) The modal can combines with not to form the single word cannot. Most of the modals have contracted negated forms in n't which are commonly used in informal English: can't, mustn't, won't (from will), etc.
Again like other auxiliaries, modal verbs undergo inversion with their subject, in forming questions and in the other cases described in the article on subject-auxiliary inversion: Could you do this?; On no account may you enter. When there is negation, the contraction with not may undergo inversion as an auxiliary in its own right: Why can't I come in? (or: Why can I not come in?).
Modals verbs have a maximum of two forms; a base form and a irregular d-form. Might is the d-form of may; could is the d-form of can; would is the d-form of will; and should is the d-form of shall. But must, ought to and need have no d-forms, and none of the modal verbs have s-forms or ing-forms (mays, musting).
There are many kinds of modals: