-은

• (SK Standard/Seoul) IPA^(key): [ɯn]
• Phonetic hangul: [은]

From Middle Korean 은〮/ᄋᆞᆫ〮 (Yale: -ún/-ón), from Old Korean 隱 (*-(u)n). Attested since the very beginning of Korean writing in the first millennium. The post-vocalic form 는 (-neun) is probably formed by pre-Middle Korean reduplication, with the original form ㄴ (-n) now relegated to colloquial speech.

• 는 (-neun) — after vowels
• ㄴ (-n) — after vowels, colloquial

은 • (-eun)

1. The Korean topic marker, with various nuances according to context:
   1. Used to mark an already known topic, to which the subsequent statement applies.

      오늘은 너무 춥다. ― Oneur-eun neomu chupda. ― Today [TOP] is too cold.

      그 일은 잊어버리자. ― Geu ir-eun ijeo-beorija. ― Let's forget about that business [TOP].

      서울에는 사람이 너무 많다. ― Seour-e-neun saram-i neomu manta. ― In Seoul [TOP], there are too many people.

   2. Used to mark the topic in statements of general fact.

      한국은 작은 나라가 아닙니다. ― Han'gug-eun jageun nara-ga animnida. ― Korea [TOP] is not a small country.

      해는 매일 아침 동쪽에서 뜬다. ― Hae-neun maeil achim dongjjog-eseo tteunda. ― The sun [TOP] rises every morning in the east.

   3. what about; Used without a predicate to demand new information about an already known topic.

      이건 엄마 꺼야. ― 아빠 꺼는? ― Igeon eomma kkeo-ya. ― appa kkeo-neun? ― This is for Mom. ― And for Dad [TOP]?

      우리 형 여기 있어. ― 너희 누나는? ― Uri hyeong yeogi isseo. ― neohui nuna-neun? ― My brother is here. ― And your sister [TOP]?

   4. Used in contrastive constructions, often with an exclusive sense (i.e. this and not anything else).

      눈은 예쁘네. ― Nun-eun yeppeune. ― Her eyes [TOP] are pretty [implied: but she is otherwise not pretty.]

      친구는 많은데 절친은 없다. ― Chin'gu-neun maneunde jeolchin-eun eopda. ― She has lots of friends [TOP] but no best friend [TOP].

   5. Used with an emphatic sense.

      너 없이는 못 산다. ― Neo eopsi-neun mot sanda. ― I can't live without [TOP] you.

   6. Used to background previously known information, in order to highlight the importance of the statement which follows; the marked topic is omittable.

      난 딱히 하고 싶은 말 없어. ― na-n ttakhi hago sipeun mal eopsseo. ― I [TOP] don't have anything in particular I want to say.

• 은 (-eun) can appear after bare nouns and pronouns, adverbs, certain verbal connective suffixes (e.g. 면 (-myeon, “if”), 어서 (-eoseo, “and then”)), and most case-marking particles. It is not compatible with nominative case markers 가 (-ga) and 이 (-i), or with accusative case marker 을 (-eul); if a noun in the nominative or accusative is topic-marked, the case-marking particle cannot appear.
• The distinction between topic-marking 은 (-eun) and subject-marking 가 (-ga) and 이 (-i) is often difficult for non-fluent speakers. Essentially, 은 (-eun) is explicitly topicalizing, i.e. marking previously known information as the topic to which the new information in the subsequent statement applies, while 가 (-ga) and 이 (-i) (by virtue of not being explicitly topicalizing) has a focalizing connotation, i.e. marking the preceding word as new information introduced into the discourse. Compare the context of the following:

  너 지금 어디야? — 난 벌써 왔는데?

  neo jigeum eodiya? — na-n beolsseo wanneunde?

  Where are you? — But I[TOP]'ve already come.

  The newly introduced focus is the fact of having come.

  누가 왔어? — 내가 왔지.

  Nu-ga wasseo? - nae-ga watji.

  Who came? — I [NON-TOP] did, of course.

  The newly introduced focus is the person who has come.

• Accordingly, 은 (-eun) can only be used for a topic that is already shared knowledge to both discourse participants. In the first example below, topic-marked 오빠는 (oppa-neun) is ungrammatical because the identity of the person is not shared knowledge prior to the conversation. But once the presence of the older brother is shared knowledge, topic-marking can be used:

  누구야? — 우리 오빠가 할 말 있대.

  Nuguya? - uri oppa-ga hal mal itdae.

  Who is it? — My older brother says he has something to say.

  너희 오빠는 왜 또 한밤중에 전화하냐?

  neohui oppa-neun wae tto hanbamjung-e jeonhwahanya?

  Why is your older brother calling in the middle of the night again?

Similarly, the use of 은 (eun) in statements of general fact can be explained by the fact that the existence of e.g. Korea or the sun is already common knowledge to all discourse participants.

• When a topic-marked word or phrase is at the beginning of the sentence, it is most commonly intended as either the topic or the background information of the rest of the sentence. When it appears within a sentence, it is almost always contrastive or emphatic.

• 이 (-i), 가 (-ga) (nominative case markers)
• は (wa) (Japanese equivalent)

From Middle Korean 은/ᄋᆞᆫ (Yale: -un/on), from Old Korean 隱 (*-(u)n).

In Old Korean, a (perhaps the) primary function of this suffix was to form verbal gerunds that could function as nouns, much as English -ing-forms serve as both independent nouns and to attribute nouns adjectivally; this nominalizing usage was only vestigial in Middle Korean and is wholly defunct today.

• ㄴ (-n) — after vowels or ㄹ (l)

은 • (-eun)

1. that, which; past adnominal suffix for verbal stems, often carries a perfect meaning.

   Synonym: (nonstandard, slightly different nuance) 었는 (-eonneun)

   Coordinate terms: 던 (-deon, imperfective), 는 (-neun, present), 을 (-eul, future)

   네가 어제 빌린 사전 ― ne-ga eoje billin sajeon ― the dictionary which you borrowed yesterday

   어제 먹은 빵 ― eoje meog-eun ppang ― the bread which I ate yesterday

   퍼런 정장을 입은 남자 ― peoreon jeongjang-eul ibeun namja ― the man wearing (that put on) a deep blue suit

2. Realis adnominal suffix for adjectival stems.

   Synonym: (nonstandard, slightly different nuance) 었는 (-eonneun)

   Coordinate terms: 던 (-deon, imperfective), 을 (-eul, irrealis)

   차가운 손 ― chagaun son ― hands which are cold; cold hands

   아름다운 여인 ― areumdaun yeoin ― beautiful lady; lady who is beautiful