-이-

From Middle Korean -이〮- (-í-), an allomorph of -기〮- (Yale: -kí-, causative/passive-deriving suffix) formed by lenition of the initial consonant /k-/ in intervocalic environments. Beyond Middle Korean, the causative is the original meaning as attested in Old Korean, and the passive is a later development from the causative first attested in the written language some time between the thirteenth and fifteenth centuries.^[1][2]

• (SK Standard/Seoul) IPA^(key): [i]
• Phonetic hangul: [이]

• (after vowels): usually a change in vowel quality
  • IPA^(key): /a/ to /ɛ~e/
  • IPA^(key): /ʌ/ to /e/
  • IPA^(key): /o/ to /ø~we/
  • IPA^(key): /u/ to /y~wi/

-이- • (-i-)

1. A verbal suffix deriving the stems of causative verbs, attaching to verb or adjective stems which end in a vowel, an aspirate consonant, ㄱ (g), or ㄹ (l). No longer productive.

   Synonyms: -히- (-hi-), -리- (-ri-), -기- (-gi-), -우- (-u-), -구- (-gu-), -추- (-chu-)

   ‎먹다 (meokda, “to eat”) + ‎-이- (-i-) → ‎먹이다 (meogida, “to feed”)

   ‎높다 (nopda, “to be high”) + ‎-이- (-i-) → ‎높이다 (nopida, “to heighten”)

   ‎나다 (nada, “to exit”) + ‎-이- (-i-) → ‎내다 (naeda, “to take out”)

2. A verbal suffix deriving the stems of passive verbs, mainly attaching to verb stems ending in a vowel or in an aspirate consonant. No longer productive.

   Synonyms: -히- (-hi-), -리- (-ri-), -기- (-gi-)

   ‎놓다 (nota, “to place”) + ‎-이- (-i-) → ‎놓이다 (noida, “to be placed”)

   ‎보다 (boda, “to see”) + ‎-이- (-i-) → ‎보이다 (boida, “to be seen”)

   ‎바꾸다 (bakkuda, “to change”) (transitive) + ‎-이- (-i-) → ‎바뀌다 (bakkwida, “to change, to be changed”)

Although still very common in Korean, the causative/passive suffixes are no longer productive for forming new verbs. Verbs that do not already have a morphological causative or passive must employ auxiliaries:

• -게 하다 (-ge hada) for causatives
• -어지다 (-eojida) for passives

The causative/passive suffixes 이 (-i-), -히- (-hi-), -리- (-ri-), and -기- (-gi-) all stem from the same etymon, and are fairly complementary in distribution. 이 attaches to verb stems which end in a vowel or an aspirate consonant, and (in the case of causative verbs only) to stems ending in ㄱ (g) and some of those ending in ㄹ (l).

From Middle Korean -ᅌᅵ- (Yale: -ngì-, deferential/self-humbling suffix). See the main entry for more.

-이- • (-i-)

1. Post-vowel and post-liquid allomorphic form of -으이- (-eu'i-, polite deferential suffix)