Onomatopoeic words are those which seem to sound like their meaning. The most obvious examples are verbs relating to the noises which animals make, e.g. cows moo and cats mew or meow.
If the vowel sound in a word is short, an onomatopoeic word usually signifies a short, sharp sound. If it is long (indicated in the International Phonetic Alphabet by ) then the word usually signifies a longer, slower sound. Compare pip /pip/ which is a short sound with peep /piip/ which is a long sound.
Particular combinations of letters have particular sound associations in English.
gr– at the beginning of a word can suggest something unpleasant or miserable, e.g. groan [make a deep sound forced out by pain or despair], grumble [complain in a bad-tempered way], grumpy [bad-tempered], grunt [make a low, rough sound like pigs do, or people expressing disagreement or boredom], growl [make a low, threatening sound].
cl– at the beginning of a word can suggest something sharp and/or metallic, e.g. click [make a short sharp sound], clang [make a loud ringing noise], clank [make a dull metallic noise, not as loud as a clang], clash [make a loud, broken, confused noise as when metal objects strike together], clink [make the sound of small bits of metal or glass knocking together]. Horses go clip-clop on the road.
sp– at the beginning of a word can have an association with water or other liquids or powders, e.g. splash [cause a liquid to fly about in drops], spit [send liquid out from the mouth], splutter [make a series of spitting sounds], spray [liquid sent through the air in tiny drops either by the wind or some instrument], sprinkle [throw a shower of something onto a surface], spurt [come out in a sudden burst].
ash– at the end of a word can suggest something fast and violent, e.g. smash [break violently into small pieces], dash [move or be moved violently], crash [strike suddenly violently and noisily], bash [strike heavily so as to break or injure], gash [a long deep cut or wound].
wh– at the beginning of a word often suggests the movement of air, e.g. whistle [a high pitched noise made by forcing air or steam through a small opening], whirr [sound like a bird’s wings moving rapidly], whizz [make the sound of something rushing through air], wheeze [breathe noisily especially with a whistling sound in the chest], whip [one of these or to hit with one of these].
-ckle, -ggle, or -zzle at the end of a word can suggest something light and repeated, e.g. trickle [to flow in a thin stream], crackle [make a series of short cracking sounds], tinkle [make a succession of light ringing sounds], giggle [laugh lightly in a nervous or silly way], wriggle [move with quick short twistings], sizzle [make a hissing sound like something cooking in fat], drizzle [small, fine rain].