For a look at how the English language has changed over time, check out The Distance Machine.
The Distance Machine shows words in a selection of text that were unusual at a given point in time. The site is very easy to use. You can enter text of your own or choose a passage from some previously published work in the Google Books corpus. A slider allows you to choose a year from 1800 to 2014; words in the text are highlighted in different colors to show which are more common earlier, later, or both when compared to the given year.
You can also look up just one word to see its frequency of use. I tried the word “computer.” The word appeared slightly before 1950, peaked in around the mid-70s, and more or less leveled off in the 2000s (maybe as other devices such as laptops became popular?).