Perhaps you are thinking of onomatopoeia, which is the use of words that imitate the sounds they describe. Here are some examples from *Frankenstein*:
* "The wind howled and whistled through the crevices of the house." The words "howled" and "whistled" mimic the sounds of the wind.
* "The creature's footsteps echoed in the deserted street." The word "echoed" imitates the sound of the footsteps.
* "The monster roared with rage." The word "roared" mimics the sound of the monster's voice.
These are just a few examples of onomatopoeia in *Frankenstein*. Shelley uses these sounds to create a more immersive and evocative reading experience.