Onomatopoeia in Japanese are usually written in katakana. Vowel elongation is indicated with the em-dash ('—') instead of by glyph repetition or macron.

For this writeup, I'll use the Hepburn romanization except that I'll use a double dash ('--') to indicate vowel elongation. See E2 Japanese Conventions for further information on the usage of Japanese in E2 writeups.

Sounds that are not repeated below are usually not repeated in actual use. Sounds that are repeated below can be done so as many times as necessary in actual use, but usually it's just twice.

I've listed many of the sounds below with the lower/higher pitch distinction. In reality, the distinction is more complicated. Usually the "higher pitch" ("lower pitch") sounds also have the connotation of being softer (louder) or more feminine (masculine) as well.

Example of usage of Japanese onomatopoeia:

Gozen rokuji. Niwa ha shi--n to shite ita. Totsuzen, tori ga koe wo ageta. "kokekokko--." Gogo rokuji. Sumisu ikka wa te--buru wo kakonde yorugohan wo tabete ita. Musume tachi wa pecha kucha shabette ita. Sumisu san ha musha musha to salada wo tabete ita. "Kon kon kon" Dareka ga kita you da.
and the translation (sentence for sentence match)
Six A.M. The yard was quiet. Suddenly, the rooster raised his voice: "cock-a-doodle-doo!" Six P.M. The Smith family was eating dinner around the table. The daughers were talking incessantly. Mr. Smith was munching on his salad. "knock knock knock" Someone's seems to be at the door.

I've listed some example onomatopoeia below. This is by no means a complete list.

Animal Sounds

Human Motions
  • "pero pero" (higher pitch) or "bero-bero" (lower pitch) - licking
  • "kucha kucha" (louder, higher pitch) or "musha-musha" (softer, lower pitch) - chewing
  • "gero--" or "ge--" - throwing up
  • "goku" - swallowing
  • "giri giri" - grinding one's teeth
  • "pecha kucha" - talking incessantly
  • "ha ha" or "he he" - laughter (intonation same as in English)
  • "fu fu fu" - polite female laughter
  • "keta keta" (higher pitch) or "geta-geta" (lower pitch) - impolite laughter
  • "kya--" (higher pitch) or "gya--" (lower pitch) - screaming
  • "wa--n wa--n" or "e--n e--n" - crying (loud)
  • "gusu" - crying (soft)
  • "koso-koso" - sneaking around
  • "su-- su--" - breathing softly as you sleep
  • "ga-- ga--" - snoring
  • "kushun" (softer) or "hakushun" (louder) - sneezing
  • "pori pori" (higher pitch) or "bori bori" (lower pitch) - scratching (a person)
  • "hena hena" - when one is exhausted and cannot stand
  • "pito pito" - a faucet slowly leaking droplets of water
  • "ja--" - sound of a thin stream of water hitting the water surface below. Ex. running faucet
  • "sha--" (higher pitch) or "za--" (lower pitch) - sound of a large amount of water flowing - Ex. heavy rain ("za--") or a shower ("sha--")
  • "pasha pasha" (higher pitch) or "basha basha" (lower pitch) - splashing in water
  • "toro toro" (higher pitch) or "doro doro" (lower pitch) - a stream of liquid flowing or pouring.
Collision between hard objects
  • "kacha kacha" (higher pitch) or "gacha gacha" (lower pitch) - Hard noises made by a collection of small objects - banging into each other. Usually refers to a situation in which a person is responsible for the collisions.
  • "kata kata" (higher pitch) or "gata gata" (lower pitch) - Hard noises made by a single larger object - like a house or a table - when they bang into something else (table and floor) or when parts of said object bang into each other (house, car). "kata kata" is the sound made when you type at the keyboard.
  • "kan kan" (higher pitch) or "gan gan" (lower pitch) - a sound of something (usually made of metal) hitting something else and possibly making a dent, but not shattering - ex. the sound made when you hit your car hood with a bat.
  • "kon kon" (higher pitch) or "gon gon" (lower pitch) - a sound of something (usually not made of metal) hitting something else and possibly making a dent, but not shattering - ex. knocking on a wooden door.
  • "ka--n ka--n" (higher pitch) "go--n go--n" (lower pitch) - church or temple bell ringing.
  • "gassha--n" - sound of something shattering upon collision - ex. a piece of glass.
  • "kari kari" (higher pitch) or "gari gari" (lower pitch) - annoying sound made by something scraping against something else - ex. a rock against concrete
  • "kasa kasa" (higher pitch) or "gasa gasa" - soft sound made by dry objects rubbing against each other - ex. pieces of paper ("kasa kasa")
  • "pan" (higher pitch) or "ban" (lower pitch) - something exploding. Example: a balloon ("pan"), a gun ("ban")
  • "poki" (higher pitch) or "boki" (lower pitch) - breaking something long, hard and thin - ex. a pair of chopsticks, bones
  • "koro koro" (higher pitch) or "goro goro" (lower pitch) - rolling
Collision between soft objects and hard objects
  • "peta peta" - Soft noise made when an adhesive solid material - stickers, stamps - sticks to something else.
  • "pecha" (higher pitch) "becha" (lower pitch) - Soft noise made when semi-solid material - ex. apple sauce - hits a solid surface.
  • "gucha" - When you smash something - ex. a bug - and the soft material inside comes out. The object may or may not have a hard outer surface.
  • "gusa" - hard elongated shape (e.g. an arrow) sticking into a soft object (e.g. a person).
Soft objects moving
  • "kunya kunya" - Soft sound made when a flexible shape - ex. a large thin sheet of plastic - bends in a wavy manner.
  • "puyo puyo" - Sound used to describe a soft mound with lots of surface tension shakes - ex. a mound of jello.
Weather Around the home
  • "koto koto" (higher pitch) or "goto goto" (lower pitch) - a pot boiling
  • "ri--n ri--n" - a phone ringing
  • "chi--n" - microwave's done!