About combining adjectives

Question

I have some confusion I want to clarify. I understand that to combine adjectives we need to use で for な adjectives and て form of い adjectives. So I'm pretty sure that these sentences below are correct:

暖かくておいしいです - It's warm and delicious.
きれいで有名な彼女 - A beautiful & popular girl.

What I want to clarify is...

1. I wasn't sure how to combine い and な adjectives together... Can I do this?

暖かくてきれいで有名な人です - A warm, beautiful and popular person.

2. Since な adjective is basically a noun, could we use と to combine them?

あの彼女はきれいと有名です - That girl is beautiful and popular.

3. I wasn't sure if this is correct:

高くておいしくなかったです - It was expensive and didn't taste good.

Answer 1

1. Yes, you can combine both types of adjectives like that.

2. No, you can't. You have to use で.

3. Yes, that's a correct sentence. When you join two verbs using -て, ない may be applied to the two verbs as a set (see the discussion here), depending on the context. I don't think the same thing happens for two adjectives. Nevertheless, while this sentence makes sense as-is, I feel it's safer to add a comma after the first adjective.

   高くて、おいしくなかったです。

Answer 2

Based from the findings:

1. 暖かくてきれいで有名な人です combines both i-adjectives & na-adjectives. To apply this rule, just think which one is going first (i.e. i-adjective, so that 暖かい becomes 暖かくて).

2. あの彼女はきれいと有名です is incorrect usage of "と" because combining both na-adjectives requires "te-form" (picking きれいで and dropping -な at first adjective) instead of "と" particle which only used for nouns and noun phrases. So then the correct sentence should be あの彼女はきれいで有名です。

3. 高くておいしくなかったです indeed is a right sentence. The first i-adjective (高い) & second i-adjective (おいしい, using negative past form ーなかった) joined together, requires first adjective to be transformed into ーくて form (i.e. 高くて). This similar construction apply for 面白い, 暑い & other i-adjectives.

However there is one exception when combining i-adjectives: いい related suffix replaced with よくて because derived from 良い & following same conjugation with it, e.g. かっこいい => かっこよくて.

Example: あの彼女は、お金持ちで、かっこよくて、有名です。 => That girl is rich, handsome & popular.

NB: かっこいい is abbreviated form of two words merged in one: 格好 & いい. On the other hand, we know that 嫌い is another exception which this word derived from 嫌う, and it follows na-adjective rules (嫌いで, not 嫌い + くて).

Answer 3

暖かくておいしいです - It's warm and delicious.
きれいで有名な彼女 - A beautiful & popular girl.

These are grammatical. (Just 彼女 is a pronoun for a known girl though.)

1. I wasn't sure how to combine い and な adjective together... Can I do this?
温かくてきれいで有名な人です - A warm, beautiful and popular person.

It's grammatical. The Japanese and English versions exactly say the same thing.

But because of the word 有名, I tend to expect it to explain the reason of being famous like 温かくてきれいなことで有名な人です.
Another example for you: 静かで真面目で落ち着いた人です.

2. Since な adjective is basically a noun, could we use と to combine them?
あの彼女はきれいと有名です - That girl is beautiful and popular.

It's ending up saying "She is the beauty and fame itself" because you treated them as nouns.
I tend to expect it something like these:

きれいだと言われています or きれいだということで有名です。

温かいと言われています or 安い／おいしいということで有名です。

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3. I wasn't sure if this is correct
高くておいしくなかったです - It was expensive and didn't taste good

It's good, but a trick to make it smoother is ありません.
高くておいしくないです >> 高くておいしくありません。
高くておいしくなかったです >> 高くておいしくありませんでした。