-었는

Etymology
From, equivalent to the present adnominal form of the stative continuous mood, e.g. . Now grammatically equivalent to.

Usage notes

 * This suffix is considered nonstandard.
 * In colloquial Seoul Korean and in, this suffix usually appears before certain expressions conveying doubt or speculation, such as , , and.
 * In such expressions, has a nuance of emphasizing that one currently has a solid justification for such doubt or speculation.
 * For adjectives, can have a nuance of emphasizing both that the state occurred in the past and that it has a continuing impact on the present. Compare simple, which can be either past or present and is hence ambiguous (and out of context usually tends to refer to the present), and , which can have a nuance that the state no longer pertains to the present.
 * In Gyeongsang Korean, this suffix is essentially in free variation with . There is apparently no semantic difference between the two.