The Japanese adjectives are sorted into two groups;
i-adjective and na-adjective.
i-adjectives
As examples, atsui "hot,"
takai "expensive" and ookii "big" are cited.
The reason why they are called the i-adjectives is that all of them end with
-i.
The i-adjective itself conjugates to have the affirmative,
the negative, the past affirmative and the past negative forms. Each form can be made by changing the last,
-i as follows:
| | hot | expensive | big |
| affirmative | atsu-i | taka-i | ooki-i |
| negative | atsu-kunai | taka-kunai | ooki-kunai |
| past affirmative | atsu-katta | taka-katta | ooki-katta |
| past negative | atsu-kunakatta | taka-kunakatta | ooki-kunakatta |
In the formal sentence, desu should be attached to them.
| atsu-i desu | is hot |
| atsu-kunai desu | is not hot |
| atsu-katta desu | was hot |
| atsu-kunakatta desu | was not hot |
It is a wrong usage to attach the negative form of desu, janai desu and
the past form janakatta desu like
atsui janai desu or atsui deshita.
| Kyoo wa atsui desu. | It is hot today. |
| Kyoo wa atsukunai desu. | It is not hot today. |
| Kinoo wa atsukatta desu. | It was hot yesterday. |
| Kinoo wa atsukunakatta desu. | It was not hot yesterday. |
The following four forms can be called the plain form of the i-adjective.
| atsu-i | root form |
| atsu-kunai | nai form |
| atsu-katta | ta form |
| atsu-kunakatta | nakatta form |
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Besides the plain form, the i-adjective has the
te form (e.g., atsu-kute) and
the conditional form (e.g., atsu-kereba).
While the particle to "and" is used to connect the nouns,
the te form is used to connect two i-adjectives.
You should not use to in such case.
|
| koohii to koocha | coffee and tea |
| kyoo to ashita | today and tomorrow |
| yasu-kute, oishii | cheap and delicious |
| ooki-kute, omoi | big and heavy |
na-adjectives
This adjective group includes hima "not busy,"
taisetsu "important," kirei "pretty" and so on.
As opposed to the i-adjective ending with
-i, the na-adjectives have no special rules.
As a matter of fact, a few of them end with -i.
As the na-adjectives do not conjugate,
the negative and the past forms of desu should help to show the negation or the past.
In view of this point, this is the same usage as with the noun.
| | easy | pretty, beautiful, clean |
| affirmative | kantan desu | kirei desu |
| negative | kantan janai desu | kirei janai desu |
| past affirmative | kantan deshita | kirei deshita |
| past negative | kantan janakatta desu | kirei janakatta desu |
| Nihon-go wa kantan desu. | The Japanese language is easy. |
| Nihon-go wa kantan janai. | The Japanese language is not easy. |
| Shiken wa kantan deshita. | The exam was easy. |
| Shiken wa kantan janakatta desu. | The exam was not easy. |
All adjectives can be used in the structure [A] wa [adjective] desu as seen above. It is also used to modify a noun in the sentence as seen below.
Modifying nouns
When the i-adjective modifies a noun, it comes before a noun in the same way as English. When the na-adjective modifies a noun, you should put na before the noun. And you need to put no when a noun explains another noun.
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| ookii | | machi |  | big town | i-adjective + noun |
| kirei | na | machi | | pretty town | na-adjective + noun |
| Nihon | no | machi | | Japanese town | noun + noun |
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| ii | | hito | | nice person | i-adjective + noun |
| yuumei | na | hito | | famous person | na-adjective + noun |
| kaisha | no | hito | | person from my office | noun + noun |
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These are the noun phrases. Each of them can be either a subject, or an object,
or the various parts of the sentence.
| Tokyo wa ookii machi desu. |
| Watashi wa yuumei na hito ni aimashita. |