According to Bickford (1991: 17), morphology is often devided into two main categories, namely derivational morphology and inflectional morphology.
1. Derivational morphology takes a word and changes it to another word, that is, creating new lexical entries. In the most clear cases, derivational morphology creates a new word from other syntactical categories.
2. Inflectional morphology does not change a word to another word and never change syntactical categories, on the contrary, it produces other forms from the same words.
There are three other important differences between inflection and derivation. Those differences are as follow:
a. The first differences refers to productivity. Inflectional morphology is very productive, while derivational morphology is usually not productive. This means that if the students take an inflectional suffix which usually occurs with verbs, then add it to the words that are newly formed or borrowed.
b. The second differences, derivational affixes cannot be used like this. Derivational affixes often cannot be used even to words that have been in that language for centuries. Of course, there are derivational affixes which are more very productive than the others. The suffix-er, for example, in English is relatively productive.
c. The third differences is that derivational affixes often have lexical meaning, while inflectional suffixes usually have gramatical meanings. For example, the meaning of er in english can be stated as “someone who…”, but the meaning of ed must be stated with the technical term past tense.
3. Noun
A noun is often defined as a word which names a person, place or thing.
Here are some examples of nouns: boy, river, friend, Mexico, triangle, day, school, truth, university, idea, John F. Kennedy, movie, aunt, vacation, eye, dream, flag, teacher, class, grammar. John F. Kennedy is a noun because it is the name of a person; Mexico is a noun because it is the name of a place;
and boy is a noun because it is the name of a thing.
Some grammar books divide nouns into 2 groups – proper nouns and common nouns. Proper nouns are nouns which begin with a capital letter because it is the name of a specific or particular person place or thing.
Some examples of proper nouns are: Mexico, John F. Kennedy, Atlantic Ocean, February, Monday, New York City, Susan, Maple Street, Burger King. If you see a word beginning with a capital letter in the middle of a sentence, it is probably a proper noun. Most nouns are common nouns and do not begin with a capital letter.
Many nouns have a special plural form if there is more than one. For example, we say one book but two books. Plurals are usually formed by
adding an -s (books) or -es (boxes) but some plurals are formed in different ways (child – children, person – people, mouse – mice, sheep – sheep).
Base on the explanation above, the researcher conludes that noun are:
a. The names of persons, places, things, feelings, or ideas. Nouns usually answer the questions who or what.
b. Nouns are often preceded by "noun markers," the words a, an, and the.
The word answering "who or what" asked after a noun marker will be a noun.
c. Nouns usually form a plural by adding an s. If the students are unsure if a word is a noun, try adding s to mean more than one. If it works, the word is probably a noun.
d. Word endings -ance, -ancy, -ence, -ice, -ion, -ity, -ment, -ness, and - ure usually form nouns.
4. Verbs
A verb is often defined as a word which shows action or state of being.
The verb is the heart of asentence – every sentence must have a verb.
Recognizing the verb is often the most important step in understanding the meaning of a sentence. In the sentence The dog bit the man, bit is the verb and the word which shows the action of the sentence. In the sentence The man is sitting on a chair, even though the action doesn‟t show much activity, sitting is the verb of the sentence. In the sentence She is a smart girl, there is no action but a state of being expressed by the verb is. The word be is different from other verbs in many ways but can still be thought of as a verb.
Unlike most of the other parts of speech, verbs change their form.
Sometimes endings are added (learn – learned) and sometimes the word itself becomes different (teach-taught). The different forms of verbs show different meanings related to such things as tense (past, present, future), person (first person, second person, third person), number (singular, plural) and voice (active, passive). Verbs are also often accompanied by verb-like words called modals (may, could, should, etc.) and auxiliaries (do, have, will, etc.) to give them different meanings.
Base on the explanation above, the researcher concludes that verbs are:
a. Verbs are words which show action or doing. All sentences must have at least one verb.
b. A few verbs, called "linking verbs," express that someone or something exists or is a certain way. Memorize them: be, am, is, are, was, were, been, being. They are always verbs.
c. Verbs change form to show a difference in time. If the students change a sentence from present to past, or past to present, the words which change are verbs.
d. Complete verbs may include two or more verbs working together and consisting of a main verb and "helping verbs." The only words that can be helping verbs are:
1) can, could, will, would, shall, should, may, might, must -- (always helping verbs).
2) Have, has, had, do, does, did, be, am, is, are, was, were, been, being -- (helping or main).
e. The endings -ify and -ize usually form verbs; -ing or -ed endings are common verb forms.
5. Adjectives
An adjective is often defined as a word which describes or gives more information about a noun or pronoun. Adjectives describe nouns in terms of such qualities as size, color, number, and kind. In the sentence The lazy dog sat on the rug, the word lazy is an adjective which gives more information about the noun dog. We can add more adjectives to describe the dog as well as in the sentence The lazy, old, brown dog sat on the rug. We can also add adjectives to describe the rug as in the sentence The lazy, old, brown dog sat on the beautiful, expensive, new rug. The adjectives do not change the basic meaning or structure of the sentence, but they do give a lot more information about the dog and the rug. As you can see in the example above, when more than one adjective is used, a comma (,) is used between the adjectives.
Usually an adjective comes before the noun that it describes, as in tall man. It can also come after a form of the word be as in The man is tall. More than one adjective can be used in this position in the sentence The man is tall, dark and handsome. In later lessons, you will learn how to make comparisons with adjectives.
Base on the explanation above, the researcher conludes that adjectives are:
a. Adjectives are words which describe only nouns. They tell what kind? or how many?
b. The noun markers a, an, and the are always adjectives.
c. Adjectives pile up in front of nouns. For example: the big, red, flashy car. All underlined words are adjectives describing the noun car.
d. Adjectives may also follow a linking verb and describe the subject of a sentence. For example: The car is big, red, and flashy.
e. The word endings -able, -ful, - ible, - ical, -ious, -ive, -y usually form adjectives.
6. Adverb
Adverbs are words which describe or modify other verbs (The thief ran quickly). Adverbs also modify adjectives (The really dumb thief looked right into the security camera). Adverbs may also modify other adverbs (The police very easily arrested the dumb thief). Adverbs will often indicate frequency: often, never, always, and usually.