Jean Aitchison's Metaphors

Crumbling Castle

 Treats English language as a beautiful old building with gargoyles and pinnacles which need to be preserved.

Assumes at some point the language was perfect.

Infectious Disease

View that changes are caught from those around us and infect the language, particularly related to Americanisms - English has taken from other languages throughout history

Damp Spoon 

Implies that sloppiness and laziness cause much of language change (glottal stop disputes this)

Frog In A Well 

Chinese folk tale - one day it hopped out and was astonished to find what a limited view of the world it had.