"All languages change through time, but how they change, what drives these changes, and what kinds of changes we can expect may not be obvious. By comparing different languages, different dialects of the same language, or different historical stages of the same language, we can discover the history of languages."
Vedrana Mihalicek and Christina Wilson (Eds.) 2011. Language Files: Materials for an Introduction to Language and Linguistics. Columbus: The Ohio State University Press, 522.
Randall Munroe. "Xkcd: Period Speech." Xkcd.com, 2 July 2015. <http://xkcd.com/771/>.
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