I find Japanese to be YUNIIKU ("unique") in many respects. One of the most fascinating aspects of Japanese (aside from the enormous number of GAIRAIGO 外來語 ["loanwords"]) is the large amount of onomatopoeic expressions that may be drawn upon to add spice to almost anything that one wishes to say.
The immediate cause of my current reflections on Japanese onomatopoeia is a nifty translation aid for Japanese that goes by the name Perapera-kun ("Mr. Perapera"). (There's also a version for Chinese.)
Although I didn't know offhand exactly what PERAPERA meant, I could tell from its form that it must be an onomatopoeic term. When I looked PERAPERA up in my little Kenkyusha and Sanseido dictionaries, I discovered that as an adverb it indicates "fluently, glibly, volubly," as a verb it means "prattle, gibber, chatter, gab, rattle (on)," and as an adjective it describes something that is "thin, flimsy, skinny."
For a small sampling of colorful Japanese onomatopoeia, take a peek at this list. A more extensive collection, with a small bibliography and useful notes, may be found at here. A few months ago, we briefly reviewed Taro Gomi's An Illustrated Dictionary of Japanese Onomatopoeic Expressions ("Waza waza", 4/20/2008.) And some other Language Log discussions of the onomatopoeic words sometimes called ideophones are indexed here.
Manga and anime are particularly rich in onomatopoeic expressions, and that is where I have learned most of the ones I know. The MIT anime site that I just cited includes for PERAPERA mention of a joke in Azumanga Daioh (a video clip of the opening animation for this series is here): a foreigner approaches Nyamo-sensei and Yukari-sensei and tries to talk to them. His speech consists solely of "PERAPERA" repeated over and over again.
While I would not advise novices to emulate this hapless fellow, I can assure one and all that a little onomatopoeia goes a long way. During my first year of studying Mandarin long ago, I assiduously read through the whole of this wonderful old book:
Jozef MULLIE, The structural principles of the Chinese language: An introduction to the spoken language (Northern Pekingese dialect), 3 volumes. Translated from the Flemish by A. Omer Versichel. Peiping, Bureau of Engraving and Printing, 1932-37.
In these marvelous volumes, I encountered countless Pekingese onomatopoeic expressions. One that has stuck with me for more than four decades is SHABULENGDENGDE ("daffy") — I think that it was from Father Mullie's book that I learned this word. Whenever I utter SHABULENGDENGDE among Chinese acquaintances, they are stunned that I would know such an authentic expression from spoken Pekingese.
Thank you, Father Mullie, for teaching me real spoken language, not the usual textbook variety that is thrown at students!