A ‣ What are onomatopoeic words? 
Onomatopoeic words are those which seem to sound like their meaning. The most obvious examples are verbs for the noises which animals make.
B ‣ Letters, sounds and their associations 
Certain combinations of sounds have particular associations in English.
- gr- at the beginning of a word can suggest something unpleasant or miserable, e.g.
She was groaning with pain. [make a deep sound forced out by pain or despair]
Everyone was grumbling about the quality of the food. [complain in a bad-tempered way]
Don't be so grumpy! [bad-tempered]
The teacher growled angrily at the boys. [make a deep, threatening sound, like an angry dog] - cl- at the beginning of a word can suggest something sharp and/or metallic, e.g.
Click on 'log in' to enter the website. [make a short sharp sound]
There was a loud clang as the metal bar hit the stone floor. [make a loud ringing noise]
Horses go dip-clop on the road. - sp- at the beginning of a word can suggest water or other liquids or powders, e.g.
She splashed water over her face to wake herself up. [cause a liquid to fly about in drops]
The meat was horrible and she spat it out. [send liquid or food out from the mouth]
I never use hair sprays. [to spray = send liquid through the air in tiny drops either by the wind or some instrument]
He sprinkled sugar on his breakfast cereal and ate it quickly. [scatter small drops]
Water was spurting out of the broken pipe. [come out in a sudden burst] - wh- at the beginning of a word often suggests the movement of air, e.g.
He whistled and the horse ran towards him. [a high-pitched noise made by forcing air or steam through a small opening]
Suddenly a large insect whizzed over my head and scared me. [make the sound of something rushing through air]
Old Mr Banks wheezed as he climbed the stairs. [breathe noisily especially with a whistling sound in the chest] - -ash at the end of a word can suggest something fast and violent, e.g.
smash [break violently into small pieces]
dash [move fast or violently]
crash [suddenly strike violently and noisily]
bash (strike heavily so as to break or injure]
mash (make soft or pulpy by beating or crushing]
gash [a long deep cut or wound]