As it is, English is the product of many languages notably Latin, Norse, French and German. Understanding the derivation of a particular word leads to an exact understanding of it's meaning. 'Decimate', as an example, relates to the destruction of one tenth. While the misuse of the word is of little relevance, or great harm to the discussions of those that do not matter, it's use in the past was deliberate and specific in it's description and losing that meaning diminishes our understanding of history. One of my pet hates is the term Devastation which may properly describe the effect a Typhoon has on a desert island and not how some random girl feels when the shop has sold out of the shoes she wanted.