In some ways, it is surprising that languages change. After all, they are passed down through the generations reliably enough for parents and children to communicate with each other. Yet linguists find that all languages change over time—albeit at different rates. For example, while Japanese has changed relatively little over 1,000 years, English evolved rapidly in just a few centuries. Many present-day speakers find Shakespeare’s sixteenth century texts difficult and Chaucer’s fourteenth century Canterbury Tales nearly impossible to read.
Credit: From Cassell's History of England - Century Edition, circa 1902 (Chaucer); design by National Science Foundation;
Translation by Joan Maling, National Science Foundation
Why They Change
Languages change for a variety of reasons. Large-scale shifts often occur in response to social, economic and political pressures. History records many examples of language change fueled by invasions, colonization and migration. Even without these kinds of influences, a language can change dramatically if enough users alter the way they speak it.
Frequently, the needs of speakers drive language change. New technologies, industries, products and experiences simply require new words. Plastic, cell phones and the Internet didn’t exist in Shakespeare’s time, for example. By using new and emerging terms, we all drive language change. But the unique way that individuals speak also fuels language change. That’s because no two individuals use a language in exactly the same way. The vocabulary and phrases people use depend on where they live, their age, education level, social status and other factors. Through our interactions, we pick up new words and sayings and integrate them into our speech. Teens and young adults for example, often use different words and phrases from their parents. Some of them spread through the population and slowly change the language.
Types of Change
Three main aspects of language change over time: vocabulary, sentence structure and pronunciations. Vocabulary can change quickly as new words are borrowed from other languages, or as words get combined or shortened. Some words are even created by mistake. As noted in the Linguistic Society of America's publication Is English Changing?, pea is one such example. Up until about 400 years ago, pease referred to either a single pea or many peas. At some point, people mistakenly assumed that the word pease was the plural form of pea, and a new word was born. While vocabulary can change quickly, sentence structure—the order of words in a sentence—changes more slowly. Yet it’s clear that today’s English speakers construct sentences very differently from Chaucer and Shakespeare’s contemporaries (see illustration above). Changes in sound are somewhat harder to document, but at least as interesting. For example, during the so-called “Great Vowel Shift” 500 years ago, English speakers modified their vowel pronunciation dramatically. This shift represents the biggest difference between the pronunciations of so called Middle and Modern English (see audio clips in "Paths of Change")
Agents of Change
Before a language can change, speakers must adopt new words, sentence structures and sounds, spread them through the community and transmit them to the next generation. According to many linguists—including David Lightfoot, NSF assistant director for social, behavioral and economic sciences—children serve as agents for language change when, in the process of learning the language of previous generations, they internalize it differently and propagate a different variation of that language.
Linguists study language change by addressing questions such as these:
- Can we trace the evolutionary path of a language?
- How do language changes spread through communities?
- How do historical circumstances influence language change?
- What is the relationship between language learning and change?