-리-

Etymology 1
From, an allomorph of  formed by lenition of the initial consonant  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.

had stopped the allomorphy of to  intervocalically, preserving it as. This continued to be the case even after was deleted in late Middle Korean, which meant that  had effectively morphed to, as simple  without some initial consonant would lead to a realization of  as.

Usage notes
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:


 * for causatives
 * for passives

The causative/passive suffixes, , , and all stem from the same etymon, and are fairly complementary in distribution. -리- attaches to verb stems which end in, or the irregular ~  stems.