Phonestheme

Phonestheme refers to a particular sound or its sequence, which implies a certain meaning.

sn-phonestheme is usually related to the nose.

Examples: Snort, Snuff, Sniff, Sneeze, Snoop, etc.

sl-phonestheme suggests slipperiness.

Examples: Slide, Slime, Sludge, Slip, etc.

Onomatopoeia

Onomatopoeia refers to the formation of words, which (when spoken aloud) imitate the sounds related with the things/actions they refer to.

Sniff: Smell, breath, sound of inhaling air through nose, etc.

Tweet: Chirp, chirrup, chatter of a young bird, etc.

The dog was sniffing the biscuit tin.

The birds were tweeting noisily in their nests.