Grammar: Adjectives like Verbs

Now that we’ve studied how to use Japanese adjectives to modify nouns as we do in English, we’re going to examine how Japanese, unlike English, can also treat adjectives like verbs.

You should remember from Lesson 1 that –i adjectives are adjectives that end in “i” (although not every adjective that ends in “i” is an –i adjective) and –na adjectives encompass every other kind of adjective. You were told that rote memorization is the best way to identify which adjectives that end in “i” are –i adjectives and which are actually –na adjectives. Now you will learn what the difference between the two types of adjectives actually is.

-Na adjectives share characteristics with Japanese nouns and cannot be conjugated themselves. -I adjectives share characteristics with Japanese verbs because the adjectives themselves are conjugated like verbs according to tense and positive/negative rules. They can also act as a verb and be the only word in a sentence in the Plain Form.

As with Japanese verbs, there are multiple levels of formality that you can use to conjugate an adjective like a verb. We’ll concentrate on the Polite, a.k.a. Basic Formal, Form of adjectives in this lesson, as it’s better for you to err on the side of speaking too formally than too casually. However, if you would like to study the Plain, a.k.a. Informal, Form of adjectives, proceed to the Special Notes section after you have mastered this lesson.

-I Adjectives

Let’s learn the four basic conjugations of –i adjectives in the Polite Form. Throughout the lesson, we will take the –i adjective “chiisai” (small) as our first example.

Conjugating in the Polite Present Positive

1. To say, “It is [-i adjective],” simply take the –i adjective and add the formal copula “desu” (“to be”). “It is small” is therefore “chiisai desu."

Conjugating in the Polite Present Negative

1. Remove the “i” at the end of any -i adjective and you have what’s called the adjective stem. The adjective stem of “chiisai” is “chiisa-.”
2. To say, “It is not [-i adjective],” take the adjective stem of the –i adjective, add “-ku nai,” and finish the sentence with the the polite marker “desu.” “It is not small” is therefore “chiisaku nai desu.”
3. You may also hear the adjective stem added to the suffix “-ku arimasen,” without “desu.” This is also correct. “It is not small” is also “chiisaku arimasen.”

Conjugating in the Polite Past Positive

1. Remove the “i” at the end of any -i adjective and you have what’s called the adjective stem. The adjective stem of “chiisai” is “chiisa-.”
2. To say, “It was [-i adjective],” take the adjective stem of the –i adjective, add “-katta,” and finish the sentence with the polite marker “desu.” “It was small” is therefore “chiisakatta desu.”

Conjugating in the Polite Past Negative

1. Remove the “i” at the end of any -i adjective and you have what’s called the adjective stem. The adjective stem of “chiisai” is “chiisa-.”
2. To say, “It was not [-i adjective],” take the adjective stem of the –i adjective, add “-ku nakatta,” and finish the sentence with the polite marker “desu.” “It was not small” is therefore “chiisaku nakatta desu.”
3. You may also hear the adjective stem instead added to the suffix “-ku arimasen deshita.” This is also correct. “It was not small” is also “chiisaku arimasen deshita.”

*You may have noticed that "desu" is treated as a politeness marker. It is not considered a "copula" in the case of i-adjectives, but just makes the sentence more formal.

Below is a table with a few more examples:

	Present		Past
	Positive	Negative	Positive	Negative
furui (old)	furui desu	furuku nai desu furuku arimasen	furukatta desu	furuku nakatta desu furuku arimasen deshita
kawaii (cute)	kawaii desu	kawaiku nai desu kawaiku arimasen	kawaikatta desu	kawaiku nakatta desu kawaiku arimasen deshita
ii (good)*	ii desu	yoku nai desu yoku arimasen	yokatta desu	yoku nakatta desu yoku arimasen deshita

*The –i adjective “ii” (“good”) is the only –i adjective with an irregular adjective stem. Instead of “i-,” the adjective stem for “ii” is “yo-.”

Next: -na adjectives