Two pieces on language change that have appeared in the press recently offer us a really neat contrast between the big picture of change - David Crystal's The Story of English in 100 Words - and the very small details of it - Henry Hitchings' Wall Street Journal piece on the history and future of punctuation.
Crystal picks one hundred English words and uses them to trace a history of the language, taking in foreign loan words like potato and trek, a homegrown Celtic term like brock or a Scots one like wee, as well as many more recent ones from internet culture, abbreviations and cultural shifts.
Hitchings takes a look at punctuation: where it comes from and where it's going. He considers archaic forms like the pilcrow and hedera, ones that he thinks are on their way out like the apostrophe and semi-colon and ones that are coming back in or just appearing, the snark and the interrobang.
Both articles are a good read and offer some excellent examples of how to take a particular element of language - lexis in Crystal's case, orthography in Hitchings' - and trace its changes over time.