One rule of thumb is that if an adjective is written 100% in kanji, like 綺麗, it is probably a “na” adjective even if its last syllable is an い. It’s only words like 新しい that are written with an actual い that follow い rules.
Of course, there are still a handful of adjectives written with an actual い that follow “na” rules anyways, so even this rule won’t work 100% of the time. Just 95% of the time. Which isn’t half bad.
綺麗 = きれい = pretty; clean
Some Of My Best Friends Are Books
Yellow: So to figure out how to conjugate and adjective I just look at the last syllable?
Blue: Well… usually.
Blue: Some adjectives that end in い, like 綺麗 (きれい), actually follow な rules instead of い rules.
Yellow: So you would conjugate です and leave the adjective alone.
Yellow: How do I tell if an adjective follows the normal rules or not?
Blue: Most dictionaries mark whether an adjective uses い rules or な rules.
Blue: So be sure you’re familiar with your dictionary.
Yellow: Did you hear that Mr. Dictionary? My friend here thinks we need to get to know each other better.
Yellow: What’s that Mr. Dictionary? You think we should go out for ice cream? Good idea.
“ii” is one of those short common words that gets written out in hiragana more often than in kanji. You’ll be seeing いい a lot more often than 良い.
More trivia: “Yokatta”, the past tense of “good”, is also a common (but casual) stand alone sentence used to show relief and happiness. Did a friend manage to pass a difficult test? Yokatta. Did your cancer test just come back negative? Yokatta. Did a relative make it through a natural disaster unharmed? Yokatta.
良い = いい = good; ok
Good Old Days
Blue: One very important adjective is 良い (いい), which means “good” or “OK”.
Yellow: I bet that gets used a lot.
Blue: But when you conjugate いい you have to use the older pronunciation “よい”.
Yellow: More irregular conjugations. I’m not surprised.
Blue: So the past tense of いい is 良かった (よかった) and the negative is 良くない (よくない).
Yellow: And the past negative must be 良くなかった (よくなかった).
Yellow: Maybe I could just avoid conjugating いい.
Blue: You don’t think you’ll ever need a past tense “good”?
Yellow: The past is dead. Live for the present!
You don’t really hear negative adjectives all that often. People tend to say “That’s old”, not “That is not new”. The big exception is when you need to contradict or correct someone. If you get asked “Is that a new shirt?” it makes perfect sense to respond “No, it’s not new” (いいえ。あたらしくないです).
難しい = むずかしい = difficult
Why Would You Say That!?
Blue: Last time we talked about past tense adjectives.
Blue: So this time we’re going to talk about negative and past negative adjectives.
Blue: To make a negative い adjective you replace the い with くない.
Blue: To make a past negative adjective you replace the い with くなかった.
Blue: It’s a mix between the past rule and the negative rule.
Blue: Now we can say things like: 日本語は難しくないです
Yellow: I understand what you just said…
Yellow: But at the same time I don’t.
I guess you could have a language with zero conjugations, but you would have to have a ton of context in every sentence. You couldn’t just say “I went to the store”, you’d have to say “ I [go] to the store in the past”. Which would be just as much work as conjugating your verbs. So hooray for conjugation!
Some Things Never Change
Blue: When conjugating “AはBです” patterns with い adjectives you change the adjective but leave the です alone.
Blue: For example: To make a past tense sentence you change the adjective’s い to かった.
Yellow: So 新しい would become 新しかった?
Blue: That’s right.
Yellow: And we don’t use でした even though we’re in the past tense?
Blue: Right. We stick with です.
Blue: “The smartphone was new” would be スマホは新しかったです
Yellow: Not conjugating です is nice, but having to conjugate the adjective is lame.
Blue: But if you didn’t conjugate anything how would people know what tense you’re using?