-ㅅ-

Etymology
Cognate with 🇨🇬.

Etymology
From, from. Possibly cognate with the rare and ancient -s- genitive interfix in Japanese, as in.

Pronunciation
The actual underlying phoneme in Contemporary Korean remains disputed, although it was historically and is therefore written as such. The surface realization is as follows:


 * After a vowel and before an obstruent: Tensing of the subsequent obstruent (prescriptively preferred), or
 * After a sonorant consonant and before an obstruent: Tensing of the subsequent obstruent
 * Before a nasal consonant: (prescriptively preferred), or full assimilation with the nasal

Interfix

 * - from + ㅅ +, etymologically "brush of teeth"
 * - from + ㅅ +, etymologically "star of the east"
 * - from + ㅅ +, etymologically "leaf of trees"
 * - from + ㅅ +, etymologically "water of the sea"
 * - from + ㅅ +, etymologically "house of stone"
 * - from + ㅅ +, etymologically "study of eyes"
 * - from + ㅅ +, etymologically "price of things"
 * - from + ㅅ +, etymologically "point of strength"
 * - from + ㅅ +, etymologically "point of strength"

Usage notes
This morpheme can surface only in the following environments:


 * After a vowel and before a consonant or
 * After a sonorant consonant, i.e. a nasal or liquid, and before an obstruent

If it is followed by or, the interfix  intervenes between the morpheme and the second element: hence  is realized as  rather than. While the morpheme may theoretically also be present between obstruent consonants, its tensing effects are indistinguishable from the regular tensing of an obstruent when preceded by another obstruent. Therefore, its existence cannot be ascertained in those compound nouns.

The existence of the interfix in specific words varies greatly depending on age and location. Two compounds involving the same morpheme and with similar semantics may still differ in their use of the interfix: there is tensing in but not in, despite effectively identical semantics. In Sino-Korean, compare:


 * without tensing but with tensing
 * without tensing but with tensing

With compound Sino-Korean words, the interfix appears (in the form of tensing) only before certain hanja, sometimes even in non-genitive or non-attributive constructions. A leading hypothesis is that the interfix has a tendency to appear in Sino-Korean compounds which are still transparent compounds in modern Korean. For instance, is tensed in  because Koreans perceive the word as a compound of  and. It is not tensed in because  in isolation is not a valid morpheme in Korean, and the word is therefore not perceived as a compound by Korean speakers. Nonetheless, a recent study (Yu 2019) notes that it appears impossible to posit any satisfactory semantic explanation that explains all cases of Sino-Korean tensing.

The extremely common word is always preceded by the interfix in genitive constructions, and  is also very commonly preceded by it:


 * - from + ㅅ +
 * - from + ㅅ +
 * - from + ㅅ +

Contrast with non-genitive forms, with no tensing:



However, these are usually analyzed as special allomorphs of these common words, rather than as the morpheme continuing to function as a true particle.

In North Korea, the morpheme is only pronounced and not written. In the South Korean prescriptive standard, it is only written under the following conditions:


 * The first component of the compound word ends in a vowel
 * At least one of the components is a native word, with six exceptions in which it occurs in entirely Sino-Korean words.

It is unwritten in other conditions. In practice, it is often omitted even when it should prescriptively be written.

The latter criterion did not exist in South Korea until 1988, and Sino-Korean words were also prescriptively written with the morpheme if the first element ended with a vowel:


 * , instead of current ,

This was deprecated in a 1988 spelling reform, except for six words which were excluded from the reform for unclear reasons, but certain officially deprecated spellings such as for  and  for  remain widespread if nonstandard.