Nominalization -기/-음 in Korean

Overview

Nominalization turns verbs into nouns at the CEFR B2 level, using two primary suffixes: -기 and -(으)ㅁ. -기 is more common in speech and represents actions or processes, while -(으)ㅁ is more formal and represents facts or states. Both are essential for constructing complex sentences and using many grammatical patterns.

How It Works

Suffix	Usage	Example
-기	Action/process, common in speech	읽기 (reading), 쓰기 (writing)
-(으)ㅁ	Fact/state, more formal	다름 (difference), 앎 (knowing)

Common patterns with -기:

• -기 쉽다/어렵다 (easy/hard to)
• -기 전에 (before doing)
• -기로 하다 (decide to)
• -기 때문에 (because of doing)

Examples in Context

Korean	Romanization	English	Note
읽기, 쓰기, 듣기, 말하기	il-gi, sseu-gi, deut-gi, mal-ha-gi	reading, writing, listening, speaking	skill names
수영하기를 좋아해요.	su-yeong-ha-gi-reul jo-a-hae-yo	Like swimming.	-기 as object
그가 왔음을 알았어요.	geu-ga wa-sseu-meul a-ra-sseo-yo	Knew that he came.	-(으)ㅁ formal
배우기 쉬워요.	bae-u-gi swi-wo-yo	Easy to learn.	-기 쉽다
만들기 어려워요.	man-deul-gi eo-ryeo-wo-yo	Hard to make.	-기 어렵다
가기로 했어요.	ga-gi-ro hae-sseo-yo	Decided to go.	-기로 하다
다름이 없어요.	da-reu-mi eop-seo-yo	There's no difference.	-(으)ㅁ
요리하기를 싫어해요.	yo-ri-ha-gi-reul si-reo-hae-yo	Hate cooking.	-기 as object

Common Mistakes

Using -(으)ㅁ in casual speech

• Wrong: 그의 옴을 알았어 (too formal for casual)
• Right: 그가 온 것을 알았어 or 그가 온 거 알았어
• Why: -(으)ㅁ is formal/literary. In speech, -는 것 (the fact that) is more natural.

Confusing -기 with -는 것

• Wrong: Thinking they are always interchangeable
• Right: -기 is preferred with set patterns (쉽다, 어렵다, 전에, 로 하다); -는 것 is more general
• Why: Many grammar patterns specifically require -기, not -는 것.

Usage Notes

-기 appears in the four language skill names (읽기, 쓰기, 듣기, 말하기), making it visible from early learning. The pattern -기 때문에 (because) is a formal alternative to -아/어서. -기로 하다 (decide to) is extremely common. -(으)ㅁ appears mainly in formal writing and certain fixed expressions.

A key distinction worth noting: -기 is preferred in certain fixed patterns and cannot be replaced with -는 것. For example, -기 쉽다 (easy to), -기 어렵다 (hard to), -기 전에 (before doing), -기로 하다 (decide to), and -기 때문에 (because) all require -기, not -는 것. Conversely, in general object positions, both -기를 and -는 것을 are possible.

-(으)ㅁ appears in formal documents and certain fixed expressions: 다름이 아니오라 (the reason is — business email opening), 알림 (notice/notification), 건의함 (suggestion box). It also appears in the Sino-Korean compound pattern: 앎 (knowing), 죽음 (death), 삶 (life).

Practice Tips

• Practice -기 쉽다/어렵다 with various verbs: 한국어 배우기 어렵지만 재미있어요.
• Use -기로 하다 for decisions: 한국에 가기로 했어요.
• Read formal texts and identify -(으)ㅁ usage.

Related Concepts

• Prerequisite: Verb/Adj Modifying Nouns — modifier forms relate to nominalization