What is the imitation of natural sounds in word form?

Onomatopoeia

Explanation:

Onomatopoeia refers to the creation of words that imitate the sound they are trying to describe. Examples are: tic-toc, lub-dub, quack, mwah.

Onomatopoeia comes from the combination of two greek words that mean "name" and "I make".

Onomatopoeia differs a little bit between languages both in spelling and sometimes even in sound. For example, tic-toc is widely used in English, while tic-tac is used in Spanish; quack is used in English, while cuac is used in Spanish; haha is used in English and jaja is used in Spanish.