Introduction to Adjectives (い-Adjectives and な-Adjectives)
Grammatically speaking, there are two kinds of adjectives in Japanese, い-adjectives and な-adjectives.
The Plain Form of い-adjectives ends with the い character, and this form, as should be expected, expresses the adjective in the present tense. In polite speech, です is added after the adjective; and in casual speech, the adjective stands alone.
新しい (atarashii) – new
For the Negative Form of い-adjectives, the い in the Plain Form is dropped, in order to derive what is called the stem form, and either くありません or くないですis added at the end. As should be apparent, くありません is more polite than くないです. A more casual variation can also be achieved by dropping the です in くないです.
面白くありません (omoshirokuarimasen) – not interesting
When い-adjectives are used to modify nouns, the Plain Form is used, without です.
面白い人 (omoshiroi hito) – interesting person
For the most part, な-adjectives do not end with the character い but there are some particular exceptions, such as the words きれい、きらい、とくい、and ゆうめい. な-adjectives require the です at the end of the sentence to form a sentence.
Kono party wa nigiyaka desune.
(This party is lively, isn’t it?)
Kono toshokan toku ni ha shizuka desu kara totemo suki desu.
(I like this particular library a lot because it is quiet.)
な-adjectives – Negative Form
To form the Negative Form of な-adjectives, all instances of です are dropped and either ではありません or じゃありません or じゃないです is added at the end. As per the norm, ではありません is the most polite of the three, and other more casual variations can be formed by dropping instances of polite speech such as です.
静かじゃないです ( shizukajyanai desu) – not quiet
特別ではありません (tokubetsu de ha arimasen) – not special
The reason な-adjectives are called な-adjectives is because of the な character added at the end when used to modify nouns. This construct is similar to the のcharacter needed by nouns when they are used to modify other nouns.
素敵な髪型 (suteki na kamigata) – splendid hairstyle
親切な人 (shinsetsu na hito) – kind person
い-adjectives are considered the more authentic Japanese adjectives of the language because they involve a more direct conjugation, as opposed to な-adjectives that are very comparative to nouns in that they require the sentence-finalizing です and have more separated conjugations. In consideration to this, the form of な-adjectives is much more accommodating to the entry of foreign words into the Japanese language. A common observation of this that one can make is with many modern English loan-words, the な character follows; and historically speaking, most な-adjectives are Chinese loan-words.
シャイな (shy na) – shy
トロピカルな (tropical na) – tropical
When combining two adjectives in order to describe something, one must take notice of which category each adjective falls into, い-adjectives or な-adjectives.
ADJ 1 “and” ADJ 2
When an い-adjective is used first, its stem form is added with くて.
楽しくて賑やか (tanoshikute nigiyaka) – fun and lively
When a な-adjective is used first, its stem form is added with a much simpler で.
綺麗で明るい (kirei de akarui) – beautiful and bright
ADJ 1 “but” ADJ 2
When using multiple adjectives to convey alternating connotation, as in both positive and negative impressions, the conjunctive particle が is used in lieu of くて and で.
Watashi no kateikyoushi wa yasashii desuga kibishii desu.
(My tutor is nice but strict.)
When the second adjective used is subjective on behalf of the speaker, the first adjective used is understood as the preemptive reason for such judgment.