"Onomatope" is a word adopted from the French language "onomatopée". In Japanese language, we call them imitative words and mimetic words; "Giongo and Gitaigo". However, in this teaching material, we are going to use "onomatope" as a generic name which includes both imitative and mimetic words.
"Onomatope" is used frequently in the Japanese language, for example, the rain is falling heavily "ザーザー(za:za:)" and the stars are twinkling "きらきら (kirakira)". Undoubtedly every language has onomatopoeia, but it seems that despite the number of words or species, they are not as succinctly used in these other languages as they are in the Japanese language. That is the reason why Japanese language is referred to as a language fertile in onomatopoeia.
A speech sound which is expressing the natural noise of things, such as buzz, crackle, splash and wail are called imitative words. Imitative words are divided into two parts; one is non-living thing's noise such as; "heavy" rainfall : "ザーザー(za:za:)" and "tap" at the door : "トントン(tonton)" . And the other one is living thing's sound such as; "bow-wow": "ワンワン(wanwan)" and "meow": "ニャーニャー(nya:nya:)".
Mimetic words is a speech sound which describes things or living things included human being's movement, condition and situation without any sound. Mimetic words are divided into three kinds: showing the condition of non-living thing, such as "glittering" : "きらきら(kirakira)" and "slippery": "つるつる(tsurutsuru)", showing the condition of living thing such as "groggy": "ふらふら(furafura)" and "loitering": "のろのろ(noronoro)" and showing human feeling such as "impatiently": "いらいら(iraira)" and "excitedly": "わくわく(wakuwaku)" .