Korean phonology

Consonants

Korean has 19 consonant phonemes.

For each stop and affricate, there is a three-way contrast between unvoiced segments, which are distinguished as plain, tense, and aspirated.

The IPA symbol ⟨◌͈⟩, resembling a subscript double straight quotation mark, shown here with a placeholder circle, is used to denote the tensed consonants /p͈/, /t͈/, /k͈/, /t͈ɕ/, /s͈/. Its official use in the Extensions to the IPA is for strong articulation, but is used in literature for faucalized voice. The Korean consonants also have elements of stiff voice, but it is not yet known how typical that is of faucalized consonants. They are produced with a partially constricted glottis and additional subglottal pressure in addition to tense vocal tract walls, laryngeal lowering, or other expansion of the larynx. According to a recent study, this glottalization is disappearing from the "tense" consonants, while the "lax" and "aspirated" consonants are slack, particularly in the latter.

An alternative analysis proposes that the "tensed" series of sounds are (fundamentally) regular voiceless, unaspirated consonants: the "lax" sounds are voiced consonants that become devoiced initially, and the primary distinguishing feature between word-initial "lax" and "tensed" consonants is that initial lax sounds cause the following vowel to assume a low-to-high pitch contour, a feature reportedly associated with voiced consonants in many Asian languages, whereas tensed (and also aspirated) consonants are associated with a uniformly high pitch.

/p, t, tɕ, k/ are voiced [b, d, dʑ, ɡ] between voiced sounds but voiceless elsewhere. Among younger generations, they may be just as aspirated as /pʰ, tʰ, tɕʰ, kʰ/ in initial position; the primary difference is that the following vowel carries a low tone. /pʰ, tʰ, tɕʰ, kʰ/ are strongly aspirated, more so than English voiceless stops. /tɕ͈, tɕʰ, tɕ~dʑ/ may be pronounced /ts͈, tsʰ, ts~dz/ by some speakers, especially before back vowels.

The analysis of /s/ as phonologically plain or aspirated has been a source of controversy in the literature. Its characteristics are neearsest to those of plain stops, as it generally undergoes intervocalic voicing word-medially. It shows moderate aspiration word-initially, but no aspiration word-medially. /s, s͈/ are palatalized [ɕ, ɕ͈] before /i, j/.

/m, n/ tend to be denasalized word-initially. /ŋ/ appears only between vowels and in the syllable coda.

/l/ is an alveolar flap [ɾ] between vowels or between a vowel and an /h/; and is [l] or [ɭ] at the end of a word, before a consonant other than /h/, or next to another /l/. It is unstable at the beginning of a word, tending to become [n] before most vowels and silent before /i, j/, but it is commonly [ɾ] in English loanwords.

Between vowels, /h/ may either be voiced [ɦ] or become inaudible or even often disappear.

Vowels

Korean has eight vowel phonemes and a length distinction for each. Long vowels are pronounced somewhat more peripherally than short ones. Two more vowels, the mid front rounded vowel ([ø] ㅚ) and the close front rounded vowel ([y] ㅟ), can still be heard in the speech of some older speakers, but they have been largely replaced by the diphthongs [we] and [ɥi], respectively. In a 2003 survey of 350 speakers from Seoul, nearly 90% pronounced the vowel 'ㅟ' as [ɥi].

In 2012, vowel length is reported almost completely neutralized in Korean, except for a very few older speakers of Seoul dialect, for whom the the distinctive vowel-length distinction is maintained only in the first syllable of a word.

The distinction between /e/ and /ɛ/ is lost in South Korean dialects but robust in North Korean dialects. For the speakers who do not make the difference, [e̞] seems to be the dominant form. For most of the speakers who still utilize vowel length contrastively, long /ʌː/ is actually [ɘː]. In Seoul Korean, /o/ is produced higher than /ʌ/, whlie in Pyongan, /o/ is lower than /ʌ/. In Northeastern Korean tonal dialect, the two are comparable in height and the main contrast is along pitch. Within Seoul Korean, /o/ is raised toward /u/ while /ɯ/ is fronted away from /u/ in younger speakers’ speech.

Middle Korean had an additional vowel phoneme denoted by ᆞ, known as arae-a (literally "lower a"). The vowel merged with [a] in all mainland varieties of Korean but remains distinct in Jeju, where it is pronounced [ɒ].

Diphthongs and glides

Because they may follow consonants in initial position in a word, which no other consonant can do, and also because of hangul orthography, which transcribes them as vowels, semivowels such as /j/ and /w/ are sometimes considered to be elements of diphthongs rather than separate consonant phonemes.

Some analyses treat /ɯ/ as a central vowel and thus the marginal sequence /ɰi/ as having a central-vowel onset, which would be more accurately transcribed [ȷ̈i] or [ɨ̯i].

Positional allophones

Korean consonants have three principal positional allophones: initial, medial (voiced), and final (checked). The initial form is found at the beginning of phonological words. The medial form is found in voiced environments, intervocalically and after a voiced consonant such as n or l. The final form is found in checked environments such as at the end of a phonological word or before an obstruent consonant such as t or k. Nasal consonants (m, n, ng) do not have noticeable positional allophones beyond initial denasalization, and ng cannot appear in this position.

The table below is out of alphabetical order to make the relationships between the consonants explicit:

All obstruents (stops, affricates, fricatives) become stops with no audible release at the end of a word: all coronals collapse to [t̚], all labials to [p̚], and all velars to [k̚]. Final r is a lateral [l] or [ɭ].

ᄒ h does not occur in final position, though it does occur at the end of non-final syllables, where it affects the following consonant. (See below.) Intervocalically, it is realized as voiced [ɦ], and after voiced consonants it is either [ɦ] or silent.

ᄋ ng does not occur in initial position. In native Korean words, ᄅ r does not either, unlike in Chinese loans (Sino-Korean vocabulary) for which it is silent in initial position before /i/ and /j/, pronounced [n] before other vowels, and pronounced [ɾ] only in compound words after a vowel. The prohibition on word-initial r is called the "initial law" (두음법칙) in South Korea. Initial r is officially pronounced [ɾ] in North Korea. In both countries, initial r in words of foreign origin other than Chinese is pronounced [ɾ].

North Koreans pronounce ㅈ,ㅊ as [ts], [tsʰ]

Vowel assimilation

The vowel that most affects consonants is /i/, which, along with its semivowel homologue /j/, palatalizes /s/ and /s͈/ to alveolo-palatal [ɕ] and [ɕ͈] for most speakers (but see differences in the language between North Korea and South Korea). As noted above, initial |l| is silent in this palatalizing environment, at least in South Korea. Similarly, an underlying |t| or |tʰ| at the end of a morpheme becomes a phonemically palatalized affricate /tɕʰ/ when followed by a word or suffix beginning with /i/ or /j/ (it becomes indistinguishable from an underlying |tɕʰ|), but that does not happen within a word root such as /ʌti/ [ʌdi] "where?".

/kʰ/ is more affected by vowels, often becoming an affricate when followed by /i/ or /ɯ/: [kçi], [kxɯ]. The most variable consonant is /h/, which becomes a palatal [ç] before /i/ or /j/, a velar [x] before /ɯ/, and a bilabial [ɸʷ] before /o/, /u/ and /w/.

In many morphological processes, a vowel |i| before another vowel may become the semivowel /j/. Likewise, |u| and |o|, before another vowel, may reduce to /w/. In some dialects and speech registers, the semivowel /w/ assimilates into a following /e/ or /i/ and produces the front rounded vowels [ø] and [y].

Consonant assimilation

As noted above, tenuis stops and /h/ are voiced after the voiced consonants /m, n, ŋ, l/, and the resulting voiced [ɦ] tends to be elided. Tenuis stops become fortis after obstruents (which, as noted above, are reduced to [k̚, t̚, p̚]); that is, /kt/ is pronounced [k̚t͈]. Fortis and nasal stops are unaffected by either environment, though /n/ assimilates to /l/ after an /l/. After /h/, tenuis stops become aspirated, /s/ becomes fortis, and /n/ is unaffected. /l/ is highly affected: it becomes [n] after all consonants but /n/ (which assimilates to the /l/ instead) or another /l/. For example, underlying |tɕoŋlo| is pronounced /tɕoŋno/.

These are all progressive assimilation. Korean also has regressive (anticipatory) assimilation: a consonant tends to assimilate in manner but not in place of articulation: Obstruents become nasal stops before nasal stops (which, as just noted, includes underlying |l|), but do not change their position in the mouth. Velar stops (that is, all consonants pronounced [k̚] in final position) become [ŋ]; coronals ([t̚]) become [n], and labials ([p̚]) become [m]. For example, |hankukmal| is pronounced /hankuŋmal/ (phonetically [hanɡuŋmal]).

Before the fricatives /s, s͈/, coronal obstruents assimilate to a fricative, resulting in a geminate. That is, |tʰs| is pronounced /ss͈/ ([s͈ː]). A final /h/ assimilates in both place and manner, so that |hC| is pronounced as a geminate (and, as noted above, aspirated if C is a stop). The two coronal sonorants, /n/ and /l/, in whichever order, assimilate to /l/, so that both |nl| and |ln| are pronounced [lː].

There are lexical exceptions to these generalizations. For example, voiced consonants occasionally cause a following consonant to become fortis rather than voiced; this is especially common with |ls| and |ltɕ| as [ls͈] and [lt͈ɕ], but is also occasionally seen with other sequences, such as |kjʌ.ulpaŋhak| ([kjʌulp͈aŋak̚]), |tɕʰamtoŋan| ([tɕʰamt͈oŋan]) and |wejaŋkanɯlo| ([wejaŋk͈anɯɾo]).

1. Velar obstruents found in final position: ᆨ g, ᄁ kk, ᆿ k
2. Final coronal obstruents: ᆮ d, ᇀ t, ᆺ s, ᆻ ss, ᆽ j, ᆾ ch
3. Final labial obstruents: ᆸ b, ᇁ p

The resulting geminate obstruents, such as [k̚k͈], [ss͈], [p̚pʰ], and [t̚tɕʰ] (that is, [k͈ː], [s͈ː], [pʰː], and [tːɕʰ]), tend to reduce ([k͈], [s͈], [pʰ], [tɕʰ]) in rapid conversation. Heterorganic obstruent sequences such as [k̚p͈] and [t̚kʰ] may, less frequently, assimilate to geminates ([p͈ː], [kːʰ]) and also reduce ([p͈], [kʰ]).

These sequences assimilate with following vowels the way single consonants do, so that for example |ts| and |hs| palatalize to [ɕɕ͈] (that is, [ɕ͈ː]) before /i/ and /j/; |hk| and |lkʰ| affricate to [kx] and [lkx] before /ɯ/; |ht|, |s͈h|, and |th| palatalize to [t̚tɕʰ] and [tɕʰ] across morpheme boundaries, and so on.

Hangul orthography does not generally reflect these assimilatory processes, but rather maintains the underlying morphology in most cases.

Phonotactics

Korean syllable structure is maximally /CGVC/, where /G/ is a glide /j, w, ɰ/. Any consonant except /ŋ/ may occur initially, but only /p, t, k, m, n, ŋ, l/ may occur finally. Sequences of two consonants may occur between vowels, as outlined above. However, morphemes may also end in CC clusters, which are both expressed only when they are followed by a vowel. When the morpheme is not suffixed, one of the consonants is not expressed; if there is a /h/, which cannot appear in final position, it will be that. Otherwise it will be a coronal consonant, and if the sequence is two coronals, the voiceless one (/s, tʰ, tɕ/) will drop, and /n/ or /l/ will remain. Thus, no sequence reduces to [t̚] in final position.

When such a sequence is followed by a consonant, the same reduction takes place, but a trace of the lost consonant may remain in its effect on the following consonant. The effects are the same as in a sequence between vowels: an elided obstruent will leave the third consonant fortis, if it is a stop, and an elided |h| will leave it aspirated. Most conceivable combinations do not actually occur; a few examples are |lh-tɕ| = [ltɕʰ], |nh-t| = [ntʰ], |nh-s| = [ns͈], |ltʰ-t| = [lt͈], |ps-k| = [p̚k͈], |ps-tɕ| = [p̚t͈ɕ]; also |ps-n| = [mn], as /s/ has no effect on a following /n/, and |ks-h| = [kʰ], with the /s/ dropping out.

When the second and third consonants are homorganic obstruents, they merge, becoming fortis or aspirate, and, depending on the word and a preceding |l|, might not elide: |lk-k| is [lk͈].

An elided |l| has no effect: |lk-t| = [k̚t͈], |lk-tɕ| = [k̚t͈ɕ], |lk-s| = [k̚s͈], |lk-n| = [ŋn], |lm-t| = [md], |lp-k| = [p̚k͈], |lp-t| = [p̚t͈], |lp-tɕ| = [p̚t͈ɕ], |lpʰ-t| = [p̚t͈], |lpʰ-tɕ| = [p̚t͈ɕ], |lp-n| = [mn].

Among vowels, the sequences /*jø, *jɯ, *ji, *wo, *wɯ, *wu/ do not occur, and it is not possible to write them using standard hangul. The semivowel [ɰ] occurs only in the diphthong /ɰi/. There are no offglides in Korean; historical *aj, *ʌj, *uj, *oj, *ɯj have become modern /ɛ/, /e/, /ɥi/, /we/, /ɰi/.

Vowel harmony

Traditionally, the Korean language has had strong vowel harmony; that is, in pre-modern Korean, not only did the inflectional and derivational affixes (such as postpositions) change in accordance to the main root vowel, but native words also adhered to vowel harmony. It is not as prevalent in modern usage, although it remains strong in onomatopoeia, adjectives and adverbs, interjections, and conjugation. There are also other traces of vowel harmony in Korean.

There are three classes of vowels in Korean: positive, negative, and neutral. The vowel ㅡ (eu) is considered partially a neutral and negative vowel. The vowel classes loosely follow the negative and positive vowels; they also follow orthography. Exchanging positive vowels with negative vowels usually creates different nuances of meaning, with positive vowels sounding diminutive and negative vowels sounding crude:

Pitch accent

Several dialects outside Seoul retain the Middle Korean pitch accent system. In the dialect of Northern Gyeongsang, in southeastern South Korea, any syllable may have pitch accent in the form of a high tone, as may the two initial syllables. For example, in trisyllabic words, there are four possible tone patterns: