Immigration and linguistic shifts?

Question:

Immigration and linguistic shifts?

I've been reading a bit of English literature lately, both classic and modern. I've noticed that there is quite a definite shift in the language we currently use, from the English that was the language spoken at the founding of the colonies. There is, in fact, a definite shift in the past hundred years.
Other than immigration, which made certain foreign words common in daily speech, and modernization which brings new words, i.e. microwave, what do you feel is responsible for this shift?

Best Answer - Chosen by Asker:

My experience has been the we tend to make new words as we need them. The english language is very flixable in that ability. We also tend to evolve trademark names into word. Coke for example is now understood to be a carbonated beverage.