LEARN KOREAN (한국어) [GRAMMAR] #1

ADJECTIVE + ~아/어지다

Another powerful grammatical form in Korean is adding ~아/어지다 to the stem of an adjective. This changes the meaning of an adjective from "be (adjective)" to "get/become (adjective)." For example:

행복하다 - to be happy
행복해지다 - to get/become happy

춥다 - to be cold
추워지다 - to get cold

비싸다 - to be expensive
비싸지다 - to get expensive

You can technically use these adjectives in the present tense, but just like with verbs, you only ever really use the present tense conjugation to indicate common truths or to indicate the frequency of something happening. For example, you would rarely ever say:

I eat rice
But you might be more inclined to say:
I eat rice everyday

Same thing here:

날씨가 추워져 - The weather gets cold
날씨가 매일 밤에 추워져요 - The weather gets cold every night

It is more natural to use these types of words in sentences in the past/future tense:

날씨는 주말에 추워졌어 - The weather got cold over the weekend
기름 값은 비싸졌어요 - The price of oil got expensive
그 사람은 밥을 먹고 나서 행복해졌어요 - That person ate, and then became happy

When ~아/어지다 is added to an adjective, the entire construction is a verb. In practice, this is rarely an issue because most times the conjugation of an adjective and a verb is the same. However, there are some conjugation patterns that are different depending on if the word is an adjective or verb. For example, when conjugating these using the "diary form," it should be conjugated as:

날씨가 매일 밤에 추워진다 - The weather gets cold every night, instead of:
날씨가 매일 밤에 추워지다 - The weather gets cold every night

Keep this on your mind when I introduce the ~는 것 principle. In those lessons, you will learn about another grammatical principle that is treated differently depending on if it is added to verbs or adjectives. It also allows grammatical principles that otherwise wouldn't be able to be attached to adjectives to be attached to this new "verb" word.

As I mentioned earlier, you cannot attach ~고 있다 to an adjective. However, by attaching ~아/어지다 to an adjective, you can indicate that something "becomes" an adjective. It is then possible to attach ~고 있다 to an adjective that has ~아/어지다 already attached. For example:

저의 여자 친구는 예뻐지고 있어요 - My girlfriend is getting pretty
집 값은 비싸지고 있어 - House prices are getting expensive
피부가 부드러워지고 있어요 - My skin is getting soft

You learned that you cannot add ~고 싶다 to an adjective. By attaching ~아/어지다, you can indicate that something "becomes" an adjective. It is then possible to attach ~고 싶다 to an adjective as with ~고 있다. For example:

나는 행복해지고 싶어 - I want to become happy (I want to be happy)
나는 예뻐지고 싶어 - I want to become pretty (I want to be pretty)