Onomatopoeia

It has been observed (but where? I don’t recall) that to some extent all words are onomatopoeic: ‘dog’ after all is a very doggy word for native speakers. But this is a reductive notion, and as little use as limiting the meaning of onomatopoeia to the trivially obvious: boom, bang, crash, clang, murmur and the Classical Greek root of ‘barbarian’ οι βάρβαροι: the people who made a sound like ‘bar bar bar.’

Context can heighten the sense of onomatopoeia in words. A good example is in the opening lines of Kubla Khan, where Coleridge uses a restricted range of vowel sounds at the lighter end of the spectrum so that when the word ‘down’ comes at the start of line 5 it comes as a change to a lower aural register and thus enacts its meaning with its sound:

In Xanadu did Kubla Khan
A stately pleasure-dome decree:
Where Alph, the sacred river, ran
Through caverns measureless to man
   Down to a sunless sea.