Sociolinguists study contemporary variation in speech, which is language change in progress. Historical linguistics deals with longer-term change. Historical linguists can reconstruct many features of past languages by studying contemporary daughter languages.
These are languages that descend from the same parent language and that have been changing separately for hundreds or even thousands of years. We call the original language from which they diverge the protolanguage. Romance languages such as French and Spanish, for example, are daughter languages of Latin, their common protolanguage. German, English, Dutch, and the Scandinavian languages are daughter languages of proto-Germanic. The Romance languages and the Germanic languages all belong to the Indo-European language family. Their common protolanguage is called Proto-Indo-European, (PIE).
Historical linguists classify languages according to their degree of relationship (see Figure 4.2—PIE family tree). Language changes over time. It evolves—varies, spreads, divides into subgroups (languages within a taxonomy of related languages that are most closely related).
Dialects of a single parent language become distinct daughter languages, especially if they are isolated from one another. Some of them split, and new “granddaughter” languages develop. If people remain in the ancestral homeland, their speech patterns also change. The evolving speech in the ancestral homeland should be considered a daughter language like the others.
A close relationship between languages doesn’t necessarily mean that their speakers are closely related biologically or culturally, because people can adopt new languages. In the equatorial forests of Africa, “pygmy” hunters have discarded their ancestral languages and now speak those of the cultivators who have migrated to the area. Immigrants to the United States spoke many different languages on arrival, but their descendants now speak fluent English.
Knowledge of linguistic relationships often is valuable to anthropologists interested in history, particularly events during the past 5,000 years. Cultural features may (or may not) correlate with the distribution of language families. Groups that speak related languages may (or may not) be more culturally similar to each other than they are to groups whose speech derives from different linguistic ancestors. Of course, cultural similarities aren’t limited to speakers of related languages. Even groups whose members speak unrelated languages have contact through trade, intermarriage, and warfare. Ideas and inventions diffuse widely among human groups.
Many items of vocabulary in contemporary English, particularly food items such as “beef” and “pork,” come from French. Even without written documentation of France’s influence after the Norman Conquest of England in 1066, linguistic evidence in contemporary English would reveal a long period of important firsthand contact with France. Similarly, linguistic evidence may confirm cultural contact and borrowing when written history is lacking. By considering which words have been borrowed, we also can make inferences about the nature of the contact.
