Here is an interesting article in the Wall Street Journal about the evolutionary life cycle of words. It appears that a group of physicists, using data compiled by Google’s scans of books since 1800, have empirically measured how specific words emerge, persist, and fall out of use.
Language, of course, is a sporder like many others – where we can conceive of individual words as the “agents” that collectively cultivate a vocabulary that emerges among speakers. Roughly, individual words compete against other words for describing precise ideas, and certain words are collectively selected over time based on their characteristics (length, spelling, economy, phonetics, aesthetics, dialects, etc).
The authors classify their findings under the new empirical science of culture, or “culturomics” as they call it.
Unfortunately, I was unable to find the original journal article with the published findings in Science.