Unlocking Japanese Adjectives

In language learning, adjectives constitute one of the most essential elements, and Japanese is no exception. When used effectively, they enable precise descriptions of people, objects, and places. In this article, we will examine Japanese adjectives, including their types, usage, and practical strategies for mastering them.

Japanese adjectives are broadly categorized into two types: i-keiyōshi (i-adjectives) and na-keiyōshi (na-adjectives). Their usage and conjugation in a sentence vary depending on the type.

I-adjectives typically end with the “i” sound. For example: 高い (takai / tall, expensive), 寒い (samui / cold), 楽しい (tanoshii / fun, enjoyable), おもしろい (omoshiroi / interesting, funny).

Na-adjectives, on the other hand, do not end with the “i” sound. When they modify a noun, they must be followed by na. Examples include 元気 (genki / healthy, energetic), きれい (kirei / pretty, clean), 静か (shizuka / quiet), 有名 (yūmei / famous).

For learners of Japanese, understanding the distinction between these two types and applying adjectives correctly is an essential step toward using the language effectively and with confidence.

The most significant characteristic of i-adjectives is that they undergo conjugation. Similar to verbs, their form changes depending on the tense—present, past—or when expressing negation. The i at the end of an i-adjective serves as the basis for conjugation. By retaining this “i” or altering it into other forms, one can construct a variety of sentences.

Let us illustrate the conjugation patterns using 高い (takai / tall, expensive) as an example.

Present Affirmative: このビルは高いです。（Kono biru wa takai desu）
– This building is tall.

Present Negative: このビルは高くないです。（Kono biru wa takakunai desu）
– This building is not tall.

Past Affirmative: このビルは高かったです。（Kono biru wa takakatta desu）
– This building was tall.

Past Negative: このビルは高くなかったです。（Kono biru wa takakunakatta desu）
– This building was not tall.

As shown above, i-adjectives can freely change their form by making use of the i at the end.
In addition, i-adjectives can be placed directly before a noun without any additional particles.

Examples:
・寒い日 (samui hi / a cold day)
・忙しい先生 (isogashii sensei / a busy teacher)
・やさしい言葉 (yasashii kotoba / kind words)

The significant difference from na-adjectives is that i-adjectives do not require na when modifying a noun, whereas na-adjectives do.

Please note that sentences containing i-adjectives do not always have to end with -desu. For instance, one may simply say “Kono biru wa takai.” – This building is tall, which is referred to as the plain form, rather than “Kono biru wa takai desu.” – This building is tall, which is known as the polite form, used when addressing teachers, superiors, or in any situation requiring a polite tone. It is essential for learners to be able to use them correctly.

Na-adjectives are the other type of adjectives, which do not end with “i.” However, there are some exceptions, such as きれい (kirei / beautiful), which, even though it ends with “i,” requires na when modifying nouns. Examples include 静か (shizuka / quiet), 親切 (shinsetsu / kind), 有名 (yūmei / famous), and 元気 (genki / healthy, energetic).

Na-adjectives conjugate similarly to nouns. For example, using 静か (shizuka / quiet):

Present Affirmative: この部屋は静かです。 (Kono heya wa shizuka desu)
– This room is quiet.

Present Negative: この部屋は静かではありません。 (Kono heya wa shizuka dewa arimasen)
– This room is not quiet.

Past Affirmative: この部屋は静かでした。 (Kono heya wa shizuka deshita)
–This room was quiet).

Past Negative: この部屋は静かではありませんでした。 (Kono heya wa shizuka dewa arimasen deshita)
– This room was not quiet).

As you can see, the way na-adjectives are conjugated is similar to that of nouns. Therefore, when na-adjectives modify nouns, na must be placed at the end of each adjective.

Examples:
・静かな町 (shizuka na machi / a quiet town)
・有名な学校 (yūmei na gakkō / a famous school)
・元気な子ども (genki na kodomo / a healthy, energetic child)

It is important to note that forgetting to include na when using na-adjectives results in grammatically incorrect sentences. In particular, some words end with “i” but are actually na-adjectives, so special attention is required. Examples include:

・きれいな (kirei na / beautiful)
・有名な (yūmei na / famous)
・きらいな (kirai na / unpleasant / dislike)
・丁寧な (teinei na / polite, courteous)

Na-adjectives, like i-adjectives, also have a polite form and a plain form. For example, “Kono heya wa shizuka desu” – This room is quiet – is in the polite form. On the other hand, in casual conversations among friends, one might say “Kono heya wa shizuka da,” which is the plain form. Similarly, for negation, the forms change to “Shizuka dewa arimasen” (polite form) and “Shizuka dewa nai” (plain form). It is important to choose between -desu / -da and -dewa arimasen / -dewa nai appropriately depending on the situation and the person you are speaking to.

Japanese adjectives are used either to describe nouns within a sentence or as the predicate (the final part of the sentence). These rules apply to both i-adjectives and na-adjectives.

Adjectives can be placed before a noun to describe its appearance, quality, or characteristic. This usage is called attributive modification.

I-adjectives: おいしいケーキ (oishii kēki / a delicious cake)
つまらない映画 (tsumaranai eiga / a boring movie)

Na-adjectives: 有名な俳優 (yūmei na haiyū / a famous actor)
きれいな部屋 (kirei na heya / a clean room)

As shown here, i-adjectives can be placed directly before nouns; however, na-adjectives require na before each adjective.

Adjectives can describe the subject by being placed at the end of a sentence.
For instance:

・I-adjective: このケーキはおいしいです。 (Kono kēki wa oishii desu)
– This cake is delicious.

・Na-adjective: この町はにぎやかです。 (Kono machi wa nigiyaka desu)
– This town is lively.

In this way, sentences are concluded by adding endings such as -desu or -da.

Using adjectives can enrich expressions. Simply stating “a book” provides no description; however, by placing adjectives before nouns, it is possible to convey more detailed information to the reader or listener, for example, an interesting book, an old book, and a famous book.

Adjectives frequently appear in daily conversations, such as “Kyō wa samui desu ne” – It is cold today – and “Sensei wa shinsetsu deshita” – The teacher was kind. By mastering their proper usage, you will be able to speak Japanese in a more natural and enjoyable manner.

As we have explored here today, there are two types of adjectives in Japanese: i-adjectives and na-adjectives. Understanding their forms, conjugation, and relationship to nouns can greatly enrich your sentences, enabling the listener to grasp the meaning more precisely.

Here are the key points we covered today:

・I-adjectives end with “i” and can freely conjugate within a sentence.
・Na-adjectives require “na” when placed before a noun, and their conjugation is similar to that of nouns.
・Adjectives can be used to describe nouns or as the predicate at the end of a sentence.

Furthermore, adjectives can express more nuanced meanings when combined with adverbs, such as totemo (very) and amari (not very). For instance, these can be used in sentences like Totemo takai (very tall) and Amari shizuka de wa nai (not very quiet). Practicing the combination of adverbs and adjectives can greatly enhance your ability to express yourself in Japanese.

Let’s take your Japanese expression skills to the next level by thoroughly mastering the use of adjectives!

Did this article help you understand the difference between i-adjectives and na-adjectives?

It may seem difficult at first, but try using them as much as possible. Studying at TCJ ensures that even if mistakes are made, the teachers will provide kind and supportive guidance. Using Japanese will become even more enjoyable. We look forward to seeing you at TCJ!