はじめに - Hajime ni

Today's lesson will clarify the crucial difference between い(i)-adjectives and な(na)-adjectives, specifically addressing why some words that sound like they end in い (i) are actually な(na)-adjectives. This understanding is fundamental for correct Japanese sentence structure and communication.

文(ぶん)の作(つく)り方(かた) - Bun no Tsukurikata

Let's re-examine the core concept with a focus on the true ending and grammatical behavior.

1. い(i)-Adjectives (True い-ending):

• Rule: These adjectives inherently end in a single い (i) kana as part of their root form. When you remove the い (i), what's left is usually the "stem" that carries the core meaning.

• Behavior: This い (i) stays attached when modifying a noun, and it's the part that changes when conjugating for past tense or negative forms.

• Examples:

  • 高(たか)い (takai) - high, expensive. Its root is taka-.
  • 古(ふる)い (furui) - old. Its root is furu-.
  • 暑(あつ)い (atsui) - hot (weather). Its root is atsu-.
  • 面白(おもしろ)い (omoshiroi) - interesting. Its root is omoshiro-.

  Noun Modification: The い (i) remains directly before the noun.

  • 高(たか)い本(ほん) (takai hon) - an expensive book.
  • 古(ふる)い車(くるま) (furui kuruma) - an old car.

2. な(na)-Adjectives (Implicit い-ending, but not a True い-adjective):

• Rule: These adjectives appear to end in い (i) when written in hiragana (like きれい), but that い (i) is actually a part of the last syllable of the word's root, not a separate adjectival ending. If you try to remove it and treat it like an い-adjective, the word doesn't make sense or changes its meaning.

• Behavior: When modifying a noun, they require the particle な (na). When used predicatively (at the end of a sentence), the な (na) is dropped, and they are typically followed by です (desu).

• Examples:

  • きれい (kirei) - beautiful, clean. Its root is kirei. If you try to remove an 'i', you get 'kire', which isn't the adjective.
  • 有名(ゆうめい) (yuumei) - famous. Its root is yuumei.
  • 静(しず)か (shizuka) - quiet. Its root is shizuka. (This one doesn't end in い, so it's clearly a な-adjective.)
  • 親切(しんせつ) (shinsetsu) - kind. Its root is shinsetsu. (Also clearly a な-adjective).

  Noun Modification: They always need な (na) before the noun.

  • きれいな花(はな) (kirei na hana) - a beautiful flower.
  • 有名(ゆうめい)な人(ひと) (yuumei na hito) - a famous person.

Think of it this way:

• い(i)-Adjectives are like English adjectives that end in '-y' like "happy". You can say "a happy person". The '-y' is part of the adjective.
• な(na)-Adjectives that end in い (i) are more like foreign words that sound like they end in '-y' but aren't English adjectives. For example, a word like "sushi" ends in 'i' but isn't an adjective in English. You wouldn't say "a sushi person".

The best way to tell them apart is to look at the hiragana character just before the final 「い」.

Here's a simple rule of thumb that works most of the time for the N5 level:

• If the character before 「い」 has an "e" sound (like け, せ, て, ね, へ, め, れ), the word is almost always a な-adjective.
  • きれい (kirei) -> The sound is "re" (e-sound), so it's a な-adjective.
• If the character before「い」 has an "a", "i", "u", or "o" sound, it is an い-adjective.
  • あたらしい (atarashii) -> The sound is "ra" (a-sound), so it's an い-adjective.
  • おおきい (ookii) -> The sound is "o" (o-sound), so it's an い-adjective.

Let's look at a list. It's best to just memorize the common exceptions.

Common な-Adjectives that End with 「い」

These are the words that look like い-adjectives but are actually な-adjectives.

• きれい (kirei) - beautiful, clean, tidy

  • Notice it ends in れい (rei). Because the sound before い is "e", it's a な-adjective.
  • Example: きれいな へや (kirei na heya) - a clean room

• ゆうめい (yūmei) - famous

  • This one ends in めい (mei). Again, an "e" sound before い.
  • Example: ゆうめいな ひと (yūmei na hito) - a famous person

• きらい (kirai) - dislike, hateful

  • This is a very common exception to the "e-sound" rule! The sound before い is "ra", but it is a な-adjective. It's one you just have to remember.
  • Example: わたしは トマトが きらいです。 (Watashi wa tomato ga kirai desu.) - I dislike tomatoes.

So, to summarize, if a word ends with an えい (ei) sound, you can be pretty sure it's a な-adjective.

文(ぶん)化(か)的(てき)な背(はい)景(けい) - Bunkateki na Haikei

The grammatical distinction between い(i)-adjectives and な(na)-adjectives doesn't have a direct cultural explanation, but it influences how naturally you sound. Using the correct adjective type shows a deeper understanding of the language beyond just vocabulary. For example, misusing them can sound jarring to a native speaker, even if the meaning is understood. Mastering this detail is part of sounding more fluent and polite in Japanese.

例文(れいぶん) - Reibun

Let's look at more examples focusing on the ending.

1. あのホテルは新(あたら)しいです。 (Ano hoteru wa atarashii desu.) That hotel is new. (い-adjective)
2. これは古(ふる)いカメラです。 (Kore wa furui kamera desu.) This is an old camera. (い-adjective)
3. 今日(きょう)は暑(あつ)いですね。 (Kyoo wa atsui desu ne.) It's hot today, isn't it? (い-adjective)
4. 私(わたし)の先生(せんせい)は優(やさ)しいです。 (Watashi no sensei wa yasashii desu.) My teacher is kind/gentle. (い-adjective)
5. あの映画(えいが)は面白(おもしろ)いです。 (Ano eiga wa omoshiroi desu.) That movie is interesting. (い-adjective)
6. 彼女(かのじょ)はとてもきれいな人(ひと)です。 (Kanojo wa totemo kirei na hito desu.) She is a very beautiful person. (な-adjective)
7. ここはその公園(こうえん)のように静(しず)かです。 (Koko wa sono koen no yoo ni shizuka desu.) It's quiet here like that park. (な-adjective)
8. 東京(とうきょう)はにぎやかです。 (Tookyoo wa nigiyaka desu.) Tokyo is lively. (な-adjective)
9. 彼(かれ)は有名(ゆうめい)な俳優(はいゆう)です。 (Kare wa yuumei na haiyuu desu.) He is a famous actor. (な-adjective)
10. この町(まち)は便利(べんり)です。 (Kono machi wa benri desu.) This town is convenient. (な-adjective)

練習(れんしゅう)問題(もんだい) - Renshū Mondai

A. Identify whether the underlined adjective is an い(i)-adjective or a な(na)-adjective.

1. この本(ほん)は高(たか)いです。
2. あの部屋(へや)はとても静(しず)かです。
3. 彼(かれ)は元気(げんき)な学生(がくせい)です。
4. この映画(えいが)は面白(おもしろ)いです。
5. あそこはきれいな場所(ばしょ)です。

B. Fill in the blank with the correct particle (if needed) or simply rewrite the adjective form.

1. 新(あたら)しい辞書(じしょ)＿＿。 (a new dictionary)
2. きれい＿＿公園(こうえん)＿＿。 (a beautiful park)
3. 有名(ゆうめい)＿＿俳優(はいゆう)＿＿。 (a famous actor)
4. 寒(さむ)い日(ひ)＿＿。 (a cold day)
5. 親切(しんせつ)＿＿人(ひと)＿＿。 (a kind person)

練習(れんしゅう)問題(もんだい)の答(こた)え - Renshū Mondai no Kotae

A. Identify whether the underlined adjective is an い(i)-adjective or a な(na)-adjective.

1. この本(ほん)は高(たか)いです。 (い(i)-adjective)
2. あの部屋(へや)はとても静(しず)かです。 (な(na)-adjective)
3. 彼(かれ)は元気(げんき)な学生(がくせい)です。 (な(na)-adjective)
4. この映画(えいが)は面白(おもしろ)いです。 (い(i)-adjective)
5. あそこはきれいな場所(ばしょ)です。 (な(na)-adjective)

B. Fill in the blank with the correct particle (if needed) or simply rewrite the adjective form.

1. 新(あたら)しい辞書(じしょ)。
2. きれいな公園(こうえん)。
3. 有名(ゆうめい)な俳優(はいゆう)。
4. 寒(さむ)い日(ひ)。
5. 親切(しんせつ)な人(ひと)。