According to Naver Korean dictionary, '주가' is pronounced [주까], not [주가], but '효과' is pronounced [효ː과], not [효ː꽈].

I heard and am still hearing many native Korean speakers pronounce '효과' as [효ː꽈] and I wonder why there should be difference between the two.

Is there any rule on this?

  • I am not a native speaker and I am not sure if you are, but I would say, every language will have pronunciations that doesn't follow the rule, like 닭, which is regarded as 닥 usually by native speakers in terms of pronunciation, and 검은색, will be pronounced as 껌은색 by Koreans who speak also other dialects, or I tend to think, those who live in 충청도.
    – user237
    Aug 31, 2016 at 9:49
  • Most Koreans pronounce '효과' as '효꽈' even though I believe '효과' is the correct pronunciation. The only case where I hear '효과' is from TV news programs because the TV news anchors are trained to pronounce it that way.
    – Jake
    Sep 24, 2016 at 8:35
  • As of December 2017, 효과 can be pronounced as either 효ː과 or 효ː꽈.
    – Klmo
    Jun 14, 2020 at 6:43

2 Answers 2


There is a tension between what most Koreans actually speak, and what the government-sanctioned authorities (i.e., 국립국어원 National Institute of the Korean Language) think we should speak.

(Basically, descriptivism vs. prescriptivism, except that in case of Korean, unlike English, the prescriptivists are backed by the government.)

The sound of 효과 is one such case. According to the authorities, [효과] is the correct pronunciation. However, the only time I actually hear someone pronounce it that way is when I listen to a TV news. Virtually everyone else uses [효꽈].


This is 사잇소리. Basically, it's a phonetic phenomenon occurs in some compound nouns; a consonant is inserted in between two parts of the compound. (i.e. 주가 is considered as a compound 주(식) + 가(격), while 효과 is not.)

Korea Standard Language describes three conditions for 사잇소리. They are NOT rules, as they are just being descriptive and furthermore not every compound noun that fits into one of these conditions gets 사잇소리.

  1. When the following noun starts with 'ㄱ', 'ㄷ', 'ㅂ', 'ㅅ', 'ㅈ', they become fortis.
    • 주 [주] + 가 [가] -> [주까]
    • Some speakers insert /t/ as well in between: 주-가 [줃까]
  2. When the following noun starts with 'ㄴ', 'ㅁ', /n/ is inserted in between.
    • 배 [배] + 머리 [머리] -> [밴머리]
  3. When the following noun starts with '이', double /n/ are inserted in between.
    • 나무 [나무] + 잎 [입] -> [나문닙]
    • If the precoding noun has its own coda, only a single /n/ is inserted: 꽃-잎[꼰닙]
      • Note that 꽃[꼳] pronounced 꽃[꼰]- because of consonant assimilation, not by a double insertion.

Related to this, there's an orthographical regulation, 사이시옷, which tries to use 'ㅅ' to explicitly spell out 사잇소리: 사이 + 소리 -> 사잇소리[사이쏘리], + 머리 -> 뱃머리[밴머리], and 나무 + -> 나뭇잎[나문닙]. Only South Korean 맞춤범 uses 사이시옷 (see article 30 here).

There are a lot of exception cases in the 사이시옷 regulation,

  • not only because the phonetic phenomenon it's originating is not strictly applied to all cases
    • you might have noticed that 사이시옷 does not get 사이시옷, as it is not pronounced *[사이씨옫],
  • but also the regulation itself introduces many other exceptional rules
    • e.g. no Hanja-words combinations get 사이시옷, as in 주가(株價) vs *줏가, except for these six cases 곳간(庫間), 셋방(貰房), 숫자(數字), 찻간(車間), 툇간(退間), 횟수(回數).

This causes huge confusion in the everyday writings of normal people, and the regulation still gets fierce criticism from many Korean linguists even after many revisions.

  • Thank you for the answer. If No. 1 is the rule, '민가 (민간 + 가옥)' should be pronounced [민까] and apparently it is not. How can you explain it?
    – user7
    Aug 31, 2016 at 17:59
  • Edited my answer to make clear 사잇소리 is not a rule. Some compound nouns get it.
    – krim
    Aug 31, 2016 at 18:10
  • Additionally, if you think of the example rule about 사이시옷 in Hanja-compounds, this is a particularly ridiculous rule, as 셋방 gets it, whlie 월세방 does not. And, yes, of course both get 사잇소리: [섿빵] and [전섿빵] .
    – krim
    Aug 31, 2016 at 18:30
  • I didn't know you edited your answer. I corrected some typos in some Korean words and please take a look.
    – user7
    Sep 23, 2016 at 15:01
  • Well, those were intended. I just wanted to demonstrate word combinations before and after effected by 사잇소리 (or precisely 사이시옷). But thanks for suggestion. I'm making it more explicit on that.
    – krim
    Sep 23, 2016 at 16:36

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