Globally, people currently use roughly 7,500 languages, with English, Mandarin Chinese, Hindi, Spanish, Arabic and French the most common, counting native and non-native speakers. That is a lot of languages. But it is a far cry from the peak number historically.
Researchers used mathematical modeling and insights from anthropology, linguistics and demography to estimate the number of languages used globally dating back about 12,000 years to around the end of the last Ice Age, covering a chapter in time called the Holocene epoch. They identified a period spanning the first millennium B.C. and first millennium A.D. when humankind may have spoken tens of thousands of different languages.
The researchers also charted a major decline since this linguistic "golden age," due to language replacement driven by factors such as the expansion of large empires in antiquity and European colonialism in the past several centuries.
"Languages are meaningful to their communities. They carry knowledge, associations and memories," said Claire Bowern, a professor of linguistics and anthropology at Yale University in Connecticut and a leader of the study published in the journal Science.
"For scientists, languages carry huge amounts of information about the past, from where people lived to what they ate, and what they talked about. They also give us a window into the human mind," Bowern said.
Many language families arose and evolved, with written language eventually emerging, first in Mesopotamia - Sumerian written in cuneiform script - during the fourth millennium B.C., and separately in places like Egypt, China and Mesoamerica. The researchers estimated that the number topped out in a range from 30,000 to potentially more than 75,000 different languages used worldwide at any one time.
"We rarely appreciate that, until just a few thousand years ago, humanity inhabited a vastly more diverse cultural world than the one we know today," said study lead author Damian Blasi, a cognitive scientist and evolutionary anthropologist at the Catalan Institution for Research and Advanced Studies in Spain.
The researchers used some ingenuity in reaching their estimates.
"There's no direct evidence for language numbers until very recently. We cannot rely on the extremely patchy records from antiquity. But because we know a lot about the relationships between languages and societies, we can use a couple of assumptions to make a simulation model of language diversification through time," Bowern said.
The researchers used data spanning 171 extant hunter-gatherer societies in Africa, South America and Southeast Asia to assess the size of ethnolinguistic groups - each representing a distinct language - near the beginning of the Holocene. They applied that to estimates of the human population at the time.
People were dispersed in small bands around the world living as nomadic hunter-gatherers, with the onset of agriculture and the establishment of permanent settlements and more complex cultures yet to come. The researchers estimated that these scattered populations some 12,000 years ago spoke perhaps 4,500 to 6,200 languages.
As the global population gradually grew over subsequent millennia and human society changed, the number of languages expanded.
"The situation where populations are increasing and using agriculture creates more sedentary communities and is ideal for the fostering of many, many small languages," Bowern said.
Numerous major and minor languages have come and gone. Just a few examples include the Sumerian, Hittite, Akkadian and Etruscan languages, various languages used in ancient Egypt and ancient China, and some African click languages.
Bowern described some ways languages disappear.
"The people who speak that language are killed or the people who speak that language shift - or are forced to shift - to another language," Bowern said.
Bowern also noted that old languages can evolve into new languages, as Latin, the tongue of ancient Rome, morphed into languages including French, Italian and Spanish in the centuries after the Western Roman Empire expired in 476 A.D.
Colonial powers often pursued linguistic imperialism. For instance, England cracked down on the Irish language in Ireland, Spain banned indigenous languages in the Americas and Portugal barred indigenous languages in Brazil. Other examples include France prescribing French in its African colonies and Japan suppressing Korean in Korea.
Some managed to persist. For instance, languages of the Inca, Maya and Aztecs survived Spanish suppression efforts.
About half of languages used today are deemed endangered.
Bowern said that "90% of the world's population speaks 10% of the world's languages, so there are many, many languages with small numbers of speakers and signers."
