Human Language

Human Language

If you put an English speaker, a Mandarin Chinese speaker, and a Swahili speaker in the same room, chances are they'd have trouble communicating. But according to one scientific theory, they're really all speaking the same language.


Species-specific language. I'm Bob Hirshon and this is Science Update.

By one group's count, there are 6,089 languages in the world. That exact number is up for some debate. But David Lightfoot, a linguist at Georgetown University in Washington, D.C., says there's another way to count the number of languages—that maybe, there's really just one. Call it "human."


It's very different from anything else we see in the animal world. And different animals have different communication systems, and these are genetically determined. So honeybees have one sort of system, herring gulls have another system, and human beings have a certain kind of system.

Lightfoot says that system—regardless of what particular language is being spoken—has certain properties. Someone speaking "human," for example, can express themselves in sentences of any length. Another property is that words fall into categories, like nouns, verbs, and prepositions.

Lightfoot says that by looking at the common foundation of human language, scientists can start to determine what's due to genetics and what's due to environment.


And that is to say how languages are learned. So it inevitably gives you an understanding of what goes on in the acquisition process as children are acquiring their native language. And that's something we want to understand.

I'm Bob Hirshon for AAAS, the Science Society.

Making Sense of the Research

It's well known that language is a universal human trait. As long as a child is exposed to other humans at a young age, he or she will acquire a way to communicate. In fact, even a colony of deaf children in Central America spontaneously developed their own form of sign language, which was remarkably similar to the carefully planned system of American Sign Language.

Lightfoot suggests that language is not only universal among humans, but also has universal properties that are unique to the language of human beings. Almost all animals, and even some plants, have ways that they communicate with each other, from honeybee "dances" that signal the location of food to the elaborate sonic codes of dolphins and whales. But human language, whether it's spoken or signed, has some special characteristics.

One is what Lightfoot calls "infinity capacity." Any human can construct a short sentence, like "Bob ran." Or a longer one, like "Bob ran to the store to get milk." Or an even longer, complex one, like "When he realized that it was almost five o'clock, Bob ran to the store to get milk, which he needed to make the cake for his sister's birthday party." In fact, you could write a sentence about Bob that's as long as Webster's dictionary. It wouldn't get you high marks from your English teacher, but you could do it. And you could do that in any human language.

Another aspect of infinity capacity is that once you learn a human language, you can use it to say absolutely anything, whether you've heard it before or not. For example, nobody ever recited the text of Hamlet to Shakespeare; he just wrote it using the words and language rules of his native English. That's very different from birds, for example, which have a limited inventory of songs they can sing (based either on what they've heard before or genetic programming). It's kind of like the difference between a jukebox and a live musician: the musician can make up a song on the spot, but the jukebox can play only what's loaded into it.

Unlike animal language, human language is also "stimulus-independent." That means that what you say isn't necessarily tied to what happens to you. Of course, sometimes it is; if someone elbowed you in the side, you could say, "Ow! That hurt!" But you could also say "Ow! That hurt!" when you're lying comfortably in your bed, or sing the national anthem when someone elbowed you in the side. (Of course, this might get you elbowed again.) A more realistic example is when you're having lunch with a friend and suddenly bring up something funny that happened to you yesterday. Nothing in your present situation made you say that, but you did. Animal language, on the other hand, is tied to a stimulus: a feeling of pain, the sight of a predator, a desire to mate, and so on.

Understanding the common properties of human language can make other distinctions seem more arbitrary. For example, why are Mandarin and Cantonese Chinese considered one language? They're very different, and understanding one doesn't mean you'll understand the other. Norwegian and Swedish are much more similar, but we separate the language because of the border between the countries. Are Scottish English and Texas English really the same language? What about all the different types of Arabic, which are similar in writing but very different in spoken form? What about the 300 types of "Italian" spoken in Northern Italy?

The ability to separate the essential aspects of human language from the properties of a particular language can shed light on how languages develop, and where the differences come from. It can also help scientists figure out which communication techniques come from our genes, and which ones we learn from our parents and peers. And that's one small piece of the puzzle of human evolution and development.

Now try and answer these questions:

  1. What does it mean to say that there's one human language?
  2. What are the common properties of human language? Give examples.
  3. What, to you, separates one language from another? What kind of a test would you design to determine if two languages are truly different?
  4. How is understanding language important to understanding human evolution? Child development? Human society? Be specific.

For Educators

Languages of the World, by Ethnologue.com, includes an interactive database of human languages spoken worldwide.

I Love Languages is a central database of Web resources devoted to human language.

Constructed Human Languages contains information on languages that were deliberately invented, from Esperanto to Klingon.

Primate Use of Language, by Tufts University, discusses how non-human primates use language in ways that are similar to, and different from, human beings.

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