An instance of the latter kind of onomatopoeia is Pope's use of cumbersome phrases contrasted with easily spoken language to reflect his subject in the following passage from "An Essay on Criticism" (1711):
When Ajax strives some rock's vast weight to throw,
The line too labors, and the words move slow;
Not so when swift Camilla scours the plain,
Flies o'er th' unbending corn, and skims along the main.