See Korean phonology at Wikipedia for a thorough look at the sounds of Korean.
Overall Korean phonemically has these vowels and diphthongs and consonants:
- ㄱ /k/, ㄲ /k͈/, ㄴ /n/, ㄷ /t/, ㄸ /t͈/, ㄹ /l/, ㅁ /m/, ㅂ /p/, ㅃ /p͈/, ㅅ /s/, ㅆ /s͈/, ㅇ /ŋ/, ㅈ /tɕ/, ㅉ /t͈ɕ/, ㅊ /tɕʰ/, ㅋ /kʰ/, ㅌ /tʰ/, ㅍ /pʰ/, ㅎ /h/ (all of which, except for ㅇ /ŋ/, are allowed at the beginning of a phonemic syllable)
- ㅏ /a/, ㅐ /ɛ/, ㅑ /ja/, ㅒ /jɛ/, ㅓ /ʌ/, ㅔ /e/, ㅕ /jʌ/, ㅖ /je/, ㅗ /o/, ㅘ /wa/, ㅙ /wɛ/, ㅚ /ø/, ㅛ /jo/, ㅜ /u/, ㅝ /wʌ/, ㅞ /we/, ㅟ /y/, ㅠ /ju/, ㅡ /ɯ/, ㅢ /ɰi/, ㅣ /i/
Only seven consonants are allowed at the end of a phonemic syllable: ㄱ /k/, ㄴ /n/, ㄷ /t/, ㄹ /l/, ㅁ /m/, ㅂ /p/, ㅇ /ŋ/; all other consonants and clusters assimilate into these ones. Inside a word each one of these consonants can be followed by another consonant, allowing for 95 consonant clustes:
- ㄱㄲ /kk͈/, ㄱㄸ /kt͈/, ㄱㅃ /kp͈/, ㄱㅆ /ks͈/, ㄱㅉ /kt͈ɕ/, ㄱㅊ /ktɕʰ/, ㄱㅋ /kkʰ/, ㄱㅌ /ktʰ/, ㄱㅍ /kpʰ/
- ㄷㄲ /tk͈/, ㄷㄸ /tt͈/, ㄷㅃ /tp͈/, ㄷㅆ /ts͈/, ㄷㅉ /tt͈ɕ/, ㄷㅊ /ttɕʰ/, ㄷㅋ /tkʰ/, ㄷㅌ /ttʰ/, ㄷㅍ /tpʰ/
- ㅂㄲ /pk͈/, ㅂㄸ /pt͈/, ㅂㅃ /pp͈/, ㅂㅆ /ps͈/, ㅂㅉ /pt͈ɕ/, ㅂㅊ /ptɕʰ/, ㅂㅋ /pkʰ/, ㅂㅌ /ptʰ/, ㅂㅍ /ppʰ/
- ㅇㄱ /ŋk/, ㅇㄲ /ŋk͈/, ㅇㄴ /ŋn/, ㅇㄷ /ŋt/, ㅇㄸ /ŋt͈/, ㅇㅁ /ŋm/, ㅇㅂ /ŋp/, ㅇㅃ /ŋp͈/, ㅇㅅ /ŋs/, ㅇㅆ /ŋs͈/, ㅇㅈ /ŋtɕ/, ㅇㅉ /ŋt͈ɕ/, ㅇㅊ /ŋtɕʰ/, ㅇㅋ /ŋkʰ/, ㅇㅌ /ŋtʰ/, ㅇㅍ /ŋpʰ/, ㅇㅎ /ŋh/
- ㄴㄱ /nk/, ㄴㄲ /nk͈/, ㄴㄴ /nn/, ㄴㄷ /nt/, ㄴㄸ /nt͈/, ㄴㅁ /nm/, ㄴㅂ /np/, ㄴㅃ /np͈/, ㄴㅅ /ns/, ㄴㅆ /ns͈/, ㄴㅈ /ntɕ/, ㄴㅉ /nt͈ɕ/, ㄴㅊ /ntɕʰ/, ㄴㅋ /nkʰ/, ㄴㅌ /ntʰ/, ㄴㅍ /npʰ/, ㄴㅎ /nh/
- ㄹㄱ /lk/, ㄹㄲ /lk͈/, ㄹㄹ /ll/, ㄹㄷ /lt/, ㄹㄸ /lt͈/, ㄹㅁ /lm/, ㄹㅂ /lp/, ㄹㅃ /lp͈/, ㄹㅅ /ls/, ㄹㅆ /ls͈/, ㄹㅈ /ltɕ/, ㄹㅉ /lt͈ɕ/, ㄹㅊ /ltɕʰ/, ㄹㅋ /lkʰ/, ㄹㅌ /ltʰ/, ㄹㅍ /lpʰ/, ㄹㅎ /lh/
- ㅁㄱ /mk/, ㅁㄲ /mk͈/, ㅁㄴ /mn/, ㅁㄷ /mt/, ㅁㄸ /mt͈/, ㅁㅁ /mm/, ㅁㅂ /mp/, ㅁㅃ /mp͈/, ㅁㅅ /ms/, ㅁㅆ /ms͈/, ㅁㅈ /mtɕ/, ㅁㅉ /mt͈ɕ/, ㅁㅊ /mtɕʰ/, ㅁㅋ /mkʰ/, ㅁㅌ /mtʰ/, ㅁㅍ /mpʰ/, ㅁㅎ /mh/
All other clusters assimilate into these ones. The clusters ㄱㄲ /kk͈/, ㄱㅋ /kkʰ/, ㄷㄸ /tt͈/, ㄷㅆ /ts͈/, ㄷㅉ /tt͈ɕ/, ㄷㅊ /ttɕʰ/, ㄷㅌ /ttʰ/, ㅂㅃ /pp͈/, ㅂㅍ /ppʰ/, ㄴㄴ /nn/, ㄹㄹ /ll/ and ㅁㅁ /mm/ can be considered as double consonants ㄱㄲ /k͈ː/, ㄱㅋ /kːʰ/, ㄷㄸ /t͈ː/, ㄷㅆ /s͈ː/, ㄷㅉ /t͈ɕː/, ㄷㅊ /tɕːʰ/, ㄷㅌ /tːʰ/, ㅂㅃ /p͈ː/, ㅂㅍ /pːʰ/, ㄴㄴ /nː/, ㄹㄹ /lː/ and ㅁㅁ /mː/.
- When plain stops and affricates /p t tɕ k/ are followed by a vowel and preceded by a sonorant (vowel or /n l m ŋ/), they get voiced to [b d dʑ ɡ].
- When plain stops /p t k/ are not followed by a vowel, they are not released [p̚ t̚ k̚].
- The dental sonorants /n l/ are usually palatalized to [ɲ ʎ] before /i/ and especially before /j/. In South Korea [ɲ ʎ] at the beginning of a word are usually dropped in native and Sino-Korean words and this is reflected in spelling.
- The palatal affricates [tɕ dʑ t͈ɕ tɕʰ] are non-palatal in North Korea, so there they are [ts dz t͈s tsʰ].
- /kʰ/ followed by /i/ or /j/ is palatalized to [cç], /kʰ/ followed by /ɯ/ is pronounced as [kx].
- The dental fricative /s/ and its allophones are aspirated [sʰ ɕʰ ʃʰ].
- The dental fricatives /s s͈/ are palatalized to [ɕʰ ɕ͈] before /i/ and /j/ and to [ʃʰ ʃ͈] before /y/ and [ɥ], although [ʃ͈] is a very marginal sound. In North Korea it may happen that this palatalization does not occur at all.
- The dental approximant /l/ is pronounced [ɾ] when it is followed by a vowel or /h/, it is pronounced [ɭ] otherwise. /ll/ is always pronounced [ɭɭ] depending on the following vowel. At the beginning of a words it is [ɾ] although [ɭ] are also possible depending on the speaker. [ɭ] is palatalized to [ʎ] before /i/ and /j/.
- The aspirated /h/ and is pronounced [ɸ] before /u o w/, [x] before /ɯ/, [ç] before /i/ and /j/ and [h] otherwise. Between two sonorants (vowels or /n l m ŋ/) all these allophones become voiced (respectively [β ɣ ʝ ɦ]) or /h/ is just dropped.
- Nowadays /e/ and /ɛ/ are only distinguished in spelling, but have merged phonetically.
- ^ Semivowels can only come before vowels. All the semivowels coming after the vowels have been assimilated into the preceding vowel throughout the centuries.
- ^ The semivowel /ɰ/ only occurs in the diphthong /ɰi/. Usually inside a word /ɰ/ is dropped so the diphthong merges with /i/ triggering all the sound changes that it usually triggers.
- ^ Yale romanization
- ^ Vowel length is no longer realized in Seoul Korean speech, except by some elder speakers. Vowel length has also never existed in the eastern dialects, where a pitch accent is the predominant prosodic feature. Vowel length is not shown in word spelling.
- ^ Word stress is very weak; pitch accent is more relevant.