Linguistic Evolution

Earth is a veritable Tower of Babel: Up to 7000 languages are still spoken across the globe, belonging to roughly 150 language families.

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June 11, 2017 – Online MCAT CARS Practice

Question: What is your summary of the author’s main ideas. Post your own answer in the comments before reading those made by others.

Have you ever wondered why you say “The boy is playing Frisbee with his dog” instead of “The boy dog his is Frisbee playing with”? You may be trying to give your brain a break, according to a new study. An analysis of 37 widely varying tongues finds that, despite the apparent great differences among them, they share what might be a universal feature of human language: All of them have evolved to make communication as efficient as possible.

Earth is a veritable Tower of Babel: Up to 7000 languages are still spoken across the globe, belonging to roughly 150 language families. And they vary widely in the way they put sentences together. For example, the three major building blocks of a sentence, subject (S), verb (V), and object (O), can come in three different orders. English and French are SVO languages, whereas German and Japanese are SOV languages; a much smaller number, such as Arabic and Hebrew, use the VSO order. (No well-documented languages start sentences or clauses with the object, although some linguists have jokingly suggested that Klingon might do so.)

Yet despite these different ways of structuring sentences, previous studies of a limited number of languages have shown that they tend to limit the distance between words that depend on each other for their meaning. Such “dependency” is key if sentences are to make sense.

For example, in the sentence “Jane threw out the trash,” the word “Jane” is dependent on “threw”—it modifies the verb by telling us who was doing the throwing, just as we need “trash” to know what was thrown, and “out” to know where the trash went. Although “threw” and “trash” are three words away from each other, we can still understand the sentence easily.

But we might have more trouble understanding a sentence like “Jane threw the old trash sitting in the kitchen out,” because now “threw” and “trash” are four words apart and “threw” and “out” are eight words apart. We can shorten those dependency distances, and make the sentence clearer, by changing it to read “Jane threw out the old trash sitting in the kitchen.”

These observations had led some linguists to hypothesize that all of the world’s languages reduce the distance between dependent words, something called dependency length minimization (DLM). Yet the most comprehensive previous studies of this trend only covered seven languages. Although most of them did show at least some evidence for DLM, the support for it in German was weak. That finding raised doubts about whether DLM really was a universal feature of human language.

To try to resolve the question, a team led by Richard Futrell, a linguist at the Massachusetts Institute of Technology in Cambridge, analyzed 37 languages from 10 different language families to see how much they minimized dependency lengths over what would be expected by chance. In addition to major languages such as English, German, French, and Spanish, the database also included ancient Greek, Arabic, Basque, Tamil, and Telugu, one of India’s classical languages. For most of the languages, the researchers used written prose from newspapers, novels, and blogs, although for ancient Greek and Latin they relied on poetry. They crunched thousands of sentences using software designed to measure dependency lengths.

The results, published online today in the Proceedings of the National Academy of Sciences, demonstrate that all 37 languages, including German, minimize dependency lengths to degrees greater than expected by chance. Nevertheless, the team found wide variations in the extent of DLM. Thus Italian, Indonesian, and Irish showed high degrees of minimization, whereas Japanese, Korean, and Turkish showed much less. In general, SOV languages like German tend to have longer dependency lengths, although this is not a hard-and-fast rule.

Just why these variations exist is a topic for future research, the authors say. But they point out that German and many other SOV languages employ a linguistic device called “case marking,” a modification of key words in a sentence that makes it easier to distinguish the subject from the object. For example, whereas English speakers must say either “John kisses Mary” or “Mary kisses John” to know who is kissing whom, in Japanese one can say “John Mary kiss” because the case marking will make it clear. (English, an SVO language that generally does not use case markings, nevertheless has some vestiges of it from its origins in the Germanic Old English: We say “He threw the ball to her” rather than “He threw the ball to she” to make it absolutely clear who is the subject and who is the object.)

Limiting dependency length is advantageous, Futrell says, because convoluted sentences require more memory processing—and thus more energy—for both listeners and speakers who are trying to understand and be understood. Thus it makes sense that short dependency lengths became a universal feature in human language. “As language users, we have a choice of many ways of expressing ourselves,” Futrell says. “What languages don’t do is force you” into inefficient and energy-wasting use of memory stores.

The new work is a “major advance” because “it shows that DLM is a property of languages in general,” says David Temperley, a cognitive scientist at the University of Rochester (U of R) in New York. Nevertheless, he stops short of concluding that it is a “universal” or “hard-wired” feature of language, rather than a strategy that humans have developed over time to make themselves better understood. Florian Jaeger, a psycholinguist also at U of R, agrees. Jaeger says that the current paper, along with other recent research, shows that although “the bias towards efficiency is a strong factor in explaining” common features of the world’s languages, “finding a potentially universal pattern does not necessarily” mean that it is “genetically encoded.”

Adapted from Sciencemag.

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17 Comments


  1. author points out DLM is to increase efficiency of communication.
    less distance = more efficient. however, different languages have different lengths.
    Futrell = DLM
    Temperley = however, it’s not universal but general.

    Reply

  2. MI: DLM is a strategy humans have adopted over time to make communication more efficient, as supported by current, extensive research

    Reply

  3. DLM makes communication efficient, DLM =/= universal

    Reply

  4. MI: Studies found evidence that all languages studied have DLM statistically less than by choice, although varying by language with no clear linkage. Author tone: careful to note limitations of findings and that although the efficiency makes sense, still no genetic underpinning.

    Reply

  5. Theme: Making sentences as short and succinct is a universal feature seen in human languages which serves to make communication more efficient. Author explores if this feature is an evolutionary mechanism since it is ubiquitous in most languages in the world. (central)

    Only a few languages are VSO and know that no other documented languages have been known to start with the object (O).
    testable: Know which languages adopt which style

    Sentences are structured such that they reduce the number of words between S, V and O without compromising the meaning of the sentence. Researchers at MIT have shown in their work that DLM is present in all the languages to certain degrees, even German which was an unlikely candidate at the start since it apparently has a longer dependency length than most other languages.

    Case marking is used in SOV languages like German but is not generally used in English, like most SVO languages. Same researcher feels that DLM is biologically beneficial since it requires less energy and memory processing for users. He posits that this universal feature in human language may be an evolutionary drive. However other scientists do not agree that it is genetically wired into our brains to speak like that as they feel it is just a strategy that we adopted and developed over time to make us better understood.

    Tone; neutral, informative, tries to present both sides of the argument

    Reply

  6. Languages share common features because of DLM.

    Tone = neutral

    Reply

  7. MI: Language has evolved to facilitate efficient communication. This is highlighted occurrence of DLM in majority of written languages.

    Reply

  8. This passage discusses how different languages around the world usually use DLM to make speaking and understanding the language more efficient. In order to confirm this claim, researchers conducted a study on languages that are SVO, VSO, and SOV, and found that most use DLM and others use case markings for efficiency.
    Nevertheless, most researchers do not believe these dependency terms or characteristics of efficiency are universal, but instead a form of efficiency that was built over time.

    Reply

  9. (first 8 paragraphs) MIP: liming distance = clarity + universal but varies in degree; tone = neutral

    Reply

  10. New research showed that dependency length minimization (DLM) = universal property of languages.

    Reply

  11. MIP: DLM minimizes dependency length; universal in languages.
    Tone: Somewhat skeptical.

    Reply

  12. MIP:Limiting the dependancy length between words in a sentence is important, and is a strategy used amongst many languages across the world.

    Reply

  13. Futrell’s study = language = DLM + variations; short length = easy + universal btwn languages RTA(Futrell); author = neutral

    Reply

  14. Languages all have basically similar set up; hardwired
    author-neutral

    Reply

  15. MIP
    1. DLM = universal + efficient + varies by language (Note: T & J disagree; =/= universal = adaptive > genetics [universal])
    2. DLM = decrease space between dependent words

    Tone
    Neutral

    Reply

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