-더-

Etymology
From, from. The Middle Korean suffix (and presumably Old Korean, although data is rather lacking) was quite different in meaning, being closer to a simple imperfective aspect marker; see the Middle Korean entry for more. The shift to the modern nuances is first attested in texts from the late eighteenth century. preserves the original meaning.

Usage notes

 * In Standard Seoul Korean, the suffix only appears fused before certain other suffixes (given in the "Derived terms" section below), to the point that some linguists doubt whether this should be analyzed as a discrete morpheme in the standard variety of Korean. The plain declarative is the most common form in which this suffix is encountered.
 * In some dialects of Pyong'an and northern Gyeongsang, the suffix has innovated vowel harmony and appears as after yang-vowel stems.

Etymology
From.

Usage notes

 * As in the example above, the suffix could designate a purposeful action taken by the speaker in the very conversation itself. Therefore, there were none of the discourse restraints present in the modern suffix.
 * The suffix shifts to after the copula  or the conjectural suffix.
 * The suffix merges with the modulating suffix to surface as.
 * The suffix triggers a subsequent declarative suffix to shift to :, not *더〮다〮.