Grammar is an ensamble of rules regarding the formal modifications of words and their combinations in sentences. There are two kinds of units and processes which represent the components of any grammar: Morphology and Syntax. Morfology is the study of morphemes and wordsand their formal modifications of every part of speech or class words. Sybtax studies phrases (constructions) and their combinations in sentential structures.

        Morphology and Syntax are closely related, especially when we study the sense of parts of speech or the functions of classes. It would be a mistake to exclude the sense of the forms of word from Syntax. Or, on the contrary, to to consider the sense as being studied only by Syntax. Morphology does not exist independently of Syntax, because the forms of the words be unimportant, they would not exist if they has not a syntactic use and likewise, Syntax would not exist if it had no words to organize in sentences. That is why we do not a Morphology which does not take into account the use of forms and a Syntax which would not start from the the existing forms of the words. (Vraciu A.-“Lingvistica generala comparata”, 1980, pag.2)

In the same way, grammar cannot exist in isolation from Phonetics and Vocabulary. A sentence can be made up of an unlimited number of autonomous elements, everyone having a certain sense. These elements, are named Words. Words have certain phonetically and morphological particularities and at the same time they have capacity of developing certain syntactic relations. Morphology can be considered the part of Grammar which studies the classifications words in part of speech and their formal modifications – the  inflectional morphemes which mark the grammatical categories.

       The emergence of part of speech (Noun, Adjective, Verb, Pronoun) and of grammatical catgories (Gender, Number, Case, Mood) is closely related to the abstract processes of the activity of the huma brain-along the centuries. Sense perception offers us the image (representations) is given a name by the intellect. The word appears. But the word is not capable of reflecting every object, it reflects the class of objects – the notion or concept.

The notion reflects the general characteristics and at the same time, the essential characteristics of objectsand phenomena. It is a superior form of generalization, superior to that of notion (or concept) ever so more abstract is the Category. There are many catgories: casuality, quality, quantity, possibility, reality, every one expressing the generalization of some essential relation. (Vraciu A.-“Lingvistica generala comparata”, 1980, pag.207). the term lexical catgory was introduced by Chomsky (1965) to stand for what traditional grammarians called parts of speech. The term itself is buit on an analogy with the term “lexical item” and it indicates the part of speech to which a lexical item belongs.

From a lexical point of view in traditiionsl approaches , the parts of speech are classified by taking into account what they deneote (their sense): an object or entity (the Noun, the Pronoun), a characteristic or property of an object (the Adjective), a number (the Numeral), an actiion (the Verb), a characteristic of an action or cicomstance (the Adverb), the utterance of a feeling, of a physical state (the Interjection) (“Grammatica Limbii Romane”, 1966, pag. 12).

From a morphological point of view, the parts of speech are classified into two great groups: inflected and non-inflected items according to the criterion of the modification of their form meant to express the grammatical catgories of Gender, Number, Case, Person, Time, Mood, Voice. These changes in the form of words to express grammatical categories make up inflections of words, i.e. the paradigm specialized for each part of speech: declension (NS), conjugation (VS), comparison (Adjective, Adverb).

Some of these grammatical categories are extremely relevant from a syntactic point of view . thus Number, which is aninherent nominal category plays a crucialpart in the realization of syntactic Agreement or Concord between the Sunject an Predicate of any sentence or clause.

Inflected parts of speech are subject to formal modifications in order to express grammatical categories. The notion of grammatical category is one of the most important in grammar. Grammatical categories differ from one language to another, but they also have many common elements across languages that are very different in point of structure, word order, etc.

        In defining grammatical categories, some linguistics start from the grammatical sense which accompanies the lexical sense of words, others take in to account the forma determined by their meaning. Nowadays, almost all linguists accept these two ways of approaching and explaining grammatical categories (Vraciu Aritan.-“Lingvistica generala comparata”, 1980, pag.207)

The notion of Grammatical Category is a means of organizing the linguistic system, superior to the notions of grammatical Sense and grammatical Form. They cannot also exist in the presenec of sense. Grammatical category can be considered as a dilectical fusion between the two inseparable elements. Grammatical category cannot exist outside form. Grammatical category must be identified and studied ineach and every language. For instance the idea of the Plural, the Singular in Romanian noun is made obviously by the existance of the Plural, the numbers forming an opposition (casǎ, masǎ, drum, copac – case, mese, drumuri, copaci).

        We may conclude that the opoosition is a qualitative element in the organizatin of grammatical structure whose most important elemets are “grammatical sense” and “grammatical form”. We can see how important grammtical categories are in understanding a language and the variety of points of view in studying them. The variety of categories is also important and the means of expression are specific to every language too.

     Most people with some linguistic training think they know intuitively what a grammatical categoryis, although some will hesitate when they find that the noun and the verb are considered grammatical categories alongside obviously different notions like passive, tense, case, etc. A category is a set or class of elements recognized in the description of particular languages (Taina Duţescu Coliban-“Apects of English Morphology”, 2000, pag.46).

a) Noun, Verb, Adjective are called Primary catgories: they coincide more or less with the parts of speech system, or in pur terminology, with the distributional word-classes.

b) Tense, Mood, Number, Case are Secondary categories: their presence is marked by inflectional morphemes.

c) Subject, Predicate, Object are Functional Categories because they show the function of certain group of words in a sentece.

      The concept og Grammatical Category is anecessary one and its existance is founded on the realities of language grammer – always chooses, classifies and expresses varous aspects of experience  and more over, it fulfills another important  function by determinigwhich aspect of each particular experience have to be expressed. Grammatical categories determine choises obligatory for all the speckers of a language ((Taina Duţescu Coliban-“Apects of English Morphology”, 2000, pag.48).

These choices are are the of a pair (or group) of values that obligatory repflects a certain fact of language.

Thus, in many languages, English among them, the idea of plurality of objects is opposed to the idea of singular, definite is opposed to indefinite, etc.

     Traditional grammarians noticed a very important characteristic of grammatical categories: their morpho-syntactic character. According to this idea we can say that English has morpho-syntactic categories marked either by special morpheme or by certain patterings of the sentence or other syntactic devices. There are Number, Determination, Person, Gender, Case, Comparison, Voice, Tense, Aspect and Mood. The grammatical categories characteristic to Romanian language are: Gender, Number, case, Degreee of Comparison, Person, Voice, Mood and Time.

       Many grammarians who have studied English language ask themselves a very difficul question: “Do lexical categoris have meaning?…” Such a quoation assumes a relationship between syntax and semantics. The syntactic categories are in a relation of correspondence with semantic catgories such as events, processes objects, etc (Stefanescu Ioana-“English Morphology”, 2d Volume ‘The nominal and verbal catgories, 1988, pag 15). Traditional grammarians based the identification of the parts of speech on the criterion of the meaning. For instance, George Curme (“Syntax: The parts of speech”, 1953, pag. 1) definesnouns as words used as the name of the living being or lifeless thinh: Scot, tree, cat, table, Washigton, beauty. A similar definition for nouns is to be found in “ Gramatica Academiei” (1966, pag. 55): “Substantivul este partea de vorbire care se declina si denumeste obiecte in sens foarte larg, adica finite, lucruri, fenomene, actiuni, stari, insusiri, relatii”.

        Ex: tunet, copil, copilãrie, dorinta

       Sweet (“a New English Grammar”, 1981) says that “verbs are that part of spech which denote actions (sing, walk, talk), processes (grow, turn), states or conditions (dream, love). Curme (“Syntax: The parts of speech”, 1953, pag. 42) defines adjectives as “the part of speech which expresses either the kind or conditions, or state of the living being, or lifeless thing spoken of a: good boy, a lame dog”.

The traditional grammarians based their divisions into parts of speech  on the criterion of meaning for the respective word and on the inflectional endings that charcterize the respective part of speech.

        There is Henry Sweet’s description of the ten parts of speech (Sweet,  “A New English Grammar” 1981, pag 49-64).

a) Form:  Inflections

        “The inflections of nouns in English are those of number and case. As regards to numner, most lannguages distinguish between singular and plural, some having a thisrd number, the dual; English, had only singular (bee) and plural (bees). The singular express oneness, or else leaves the numer indefinite…The plural expresses more than oneness” (Sweet,  A New English Grammar 1981, pag 49).

b) Meaning

      The primary and most characteristic use of nouns as regard their meaning is to express substances.

       Substances nouns, or concrete nouns, are divided into the two main classes of common nouns (woman), and proper names (Mary). Common nouns are again subdivided into calss-nouns (woman), nad material nouns (gold). Collective nouns (goup) are  subdivision of class nouns, all other class nouns being included under the head of individual nouns.

     “The secondary use of nouns as regarded to their meaning is to express attributes and phenomena attribute, nouns being included under the common designation ‘abstract nouns’”. (Sweet, 1981, pag 61).

c) Function

        “The first grammatical function of nouns is to serve as head words.

        e.g. a generous action, a long ride” (Sweet, 1981, pag 62)

       “The secondary function of nouns is to serve as adjunct words by modifyinf other nouns or verbs” (Sweet, 1981, pag 64).

       Sweet goes on and gives the description of the adjectives, the verbs, the verbals, the adverb, the prepositions, the conjuctuions and the intejections in the chapte “ Parts of Speech in detail” (Sweet, 1981, pag 49-153) employing all the three criteria mentioned here meaning, inflectional changes and syntactic function in a sentece.