Caveat: Phenomimes and Psychomimes

All languages have onomatopoeia:  words like “woof woof” (a dog barking), or “whirr” (a spinning thing or a dragonfly), etc.  But Korean (and apparently Japanese, too) possesses an abundant class of words known as phenomimes and psychomimes.  These are words that use “sound symbolism” (q.v. in wikipedia) to represent concepts that aren’t, per se, auditory, but in a symbolic way. Most of the Korean ones include a great deal of reduplication and vowel harmony – in fact, it could be argued that these are actually some fossilized productive reduplicative semantic feature of proto-Korean, and not really “phenomimes” or “psychomimes” at all – it’s all in the definition of those concepts, I guess. Most of them are adverbial, in syntactic terms.
I love these things.  They’re one of the reasons the Korean language is magical, for me.
Some examples, from my “bible” (Korean Grammar for International Learners, by Ihm Ho Bin et al.):
반짝반짝 [ban-jjak-ban-jjak] sparklingly
슬슬 [seul-seul] gently
주렁주렁 [ju-reong-ju-reong] richly, with fullness
흔들흔들 [heun-deul-heun-deul] shakily
옹기종기 [ong-gi-jong-gi] closely together
방긋방긋 [bang-geut-bang-geut] broadly [as in a smile]
드르르 [deu-reu-reu] excellently, smoothly
부둑부둑 [bu-dok-bu-dok] damp-dry, a bit damp mostly dry
[Update: I have blogged about this topic again with many more examples, 2012-06-04 and 2012-10-19. I have also modified this original post somewhat since it’s one of the number one draws of my blog from the broader internet, when people google “phenomimes” and “psychomimes” with “korean”, and I have been crosslinked, too.]
[Update 2 (2015-10-08): I decided to create a consolidated list of examples, which I can update periodically.]