Adjectives in the Japanese language are quite simple and straightforward, although they are used and conjugated in a manner unlike English and other Indo-European Languages. In this article, I shall present all of the base rules and patterns of the Japanese adjectival system. I shall also go over the simple and clever conjugation system involving a common adjective ending integrated with the Japanese verb system.
Types of Adjectives in Japanese
There are two distinct types of adjectives in the Japanese language, "i-adjectives" (adjectives which end in the kana い) and "na-adjectives" (adjectives which often do not end with an 'i' sound and have the kana な placed at the end when they precede a substantive to modify. There are not many な adjectives which end with い, and one of the most common examples is the adjective きれい (kirei), which means 'pretty'. Colors in Japanese can be either い or な adjectives.
Basic Adjective Rules
Adjectives in Japanese are not inflected to agree with nouns in terms of number and gender. They are however, inflected to indicate past/present tense, as well as suffixed to express specific meanings often accomplished with other words in English and other European languages. To an English speaker, this may seem incredibly odd as Indo-European languages will almost always make use of an auxiliary verb(s) (such as 'was' or 'will be' in English). い adjectives in the present tense are not changed when modifying a noun, it does not matter if the adjective in question comes before or after the noun. な adjectives on the other hand do not change when they come after a noun, however they do add the kana な when they precede a noun, hence the designation な adjective. な adjectives are often written with kanji alone and frequently have endings other than い.
To conjugate an い adjective, all you need to do is drop the ending い and then add one of the endings indicating a specific tense. To conjugate a な adjective, you do not change the ending however the endings themselves are different. な adjectives are for past/present tense in the same way as a normal noun in Japanese.
お茶はときどき高いです (ochya wa tokidoki takai desu) - (Tea is sometimes expensive.)
昨日はとても暑かった日です (Kinou wa totemo atsukatta hi desu) - (Yesterday was a very hot day.)
ヌークは賑やかじゃない村です (Nuuku wa nigiyakajyanai mura desu) - (Nuuk is not a bustling village.)
い Adjective Inflection Pattern
暑い (atsui) - (Hot)
暑くない - (atsukunai) - (Is not hot)
暑かった (atsukatta) - (Was hot)
暑くなかった (atsukunakatta) - (Was not hot)
い Adjective Exception Notice
One of the most common and practical い adjectives is a partial exception to the aforementioned conjugation rules. The Japanese adjective いい (ii) - (good) takes the form (良い) (よい) (yoi) whenever it is inflected for time, condition, etc:
天気は良くないです (tenki wa yokunai desu) (The weather is not good.)
天気は良ければ (tenki wa yokereba) (If the weather is good.)
な Adjective Inflection Pattern
静か (Shizuka) - (Quiet)
静かだった (Shizuka datta) - (Was quiet)
静かじゃない(Shizuka jyanai) - (Not quiet)
静かじゃなかった (Shizuka jyanakatta) - (Was not quiet)
Japanese adjectives also have their own respective 'te' (て) form and can also be conjugated to express meanings such as excess, condition, and substantiation. The same conjugation rules apply to add these suffixes.
An adjective's 'te' (て) form is used to link multiple adjectives in a sentence, serving as a rough translation to the conjunction 'and' and its function.
To conjugate an い adjective into its respective 'te' (て) form, simply drop the ending い and replace it with くて.
To conjugate a な adjective into its respective て form, simply add で to the ending.
この寺院は大きくて広いです (kono jiin wa, ookikute hiroi desu) - (This temple is large and wide.)
彼は新設で利口な人です (kare wa shinsetsude rikouna hito desu) - (He is a kind and intelligent person.)
The excessive form is used to express an excess or too much of something. The excessive form turns every adjective into an ichidan (group 2 - る) verb.
To conjugate an い adjective into its respective excessive form, simply drop the ending い and replace it with すぎる.
For な adjectives, simply add すぎる to the ending.
そのゲームは簡単すぎる (sono geemu ha kantansugiru) - (That game is too simple).
彼の声はうるさすぎました (Kare no koe wa urusasugimashita) - (His voice was too loud.)
Clever い Conjugation Pattern
The い adjective conjugation pattern occurs more often than just base adjectives in the Japanese language. Essentially, any Japanese verb can be transformed into an adjective by conjugating it into its respective 'tai' form, expressing desire to perform an action. The 'tai' form is then conjugated just the same as any other い adjective.
飲みたいものは何ですか？ （のみたいものはなんですか？） (nomitai mono wa nan desu ka?) - (Literal translation - What is the thing that you want to drink?)
このジュースを飲みたければ - (If you want to drink this juice)
This pattern also occurs in the simple negative form conjugation for each verb, the 'nai' form.
(Literal translations) 行く - 行かない - 行かなければ (iku - ikanai - ikanakereba) - (to go - to not go - if not go)
あの店に行かなければお酒を買えません (Ano mise ni ikanakereba osake wo kaemasen) - (If you do not go to that store, you will not be able to buy beer).
な Adjective Example:
静かじゃなければすぎに出ます - (shizukajyanakereba sugu ni demasu) - (If it is not quiet, I will leave immediately.)