Explaining Linguistics with Physics
Wednesday, November 12. 2008 • Category: Automatic Mind • Comments (5) • Trackbacks (0)-->
Intro
Recently, I was asked by a student of languages what linguistics is. She was a student on the MA level, yet in the old German Magister system and her major subject was – as far as I recall – German, which includes some obligatory courses on linguistics at our University here. A simple question but not so the answer. I have been struggling for years now to find a short and easy to understand and not too wrong explanation of what computational linguistics is about, now how about linguistics? I tried it with a physics explanation which I would like to present for discussion here.
The World of Models
In physics as the common man may imagine it, people put up models. These models describe how phenomena work in nature and how one can predict the outcome of a process or experiment. However, they do not describe what these phenomena actually are. Take light. In physics, one can use particle theory to describe the behavior of light. Or wave theory. Which one to choose? This depends on the scenario. For predicting the diffraction behavior of a light beam, one would use wave theory. For explaining how solar cells work, one needs a description of the photovoltaic effect and therefore particle theory. This perspective of wave-particle duality can be extended to all matter and energy. Still, it does not state what light, matter, or energy really are. It helps physicians to describe (and predict) phenomena in nature. These descriptions will always be incomplete.
Linguists are doing a very similar thing. They are trying to find models that describe the human language. In morphology, they have a model that describes how to build plural word forms from base forms (lemmas). In syntax, there are formal descriptions that model the combination of words in a way that produces well-formed (grammatical) sentences. Yet no claim is made about what language actually is. And yet again, there are several models explaining different facets of a given phenomenon. And again, all models will be incomplete. Some researchers are working on the connection of their models and the processing of language in the human brain. Others do not care about this connection as long as their models describe a certain phenomenon correctly.
Outro
Now I am neither a physicist nor a real linguist. For the first, taking science as a major in German Gymnasium (secondary school) is not at all a qualification, and for the second the basic courses I took during my BA studies are only a little piece of a qualification. What do people think about the above idea of an explanation? One point I immediately came up with is that most people do not know enough about physics to make any connections, leaving them with more questions than they had before. Simplifying the physics model to, say, gravity and the dropping of Newtons apple would not bring in the plurality of models for explaining one and the same phenomenon.
Why should we be concerned with this explanation business anyways? Well, I think we need it. May it be to explain to our friends why we are doing these crazy things, or may it be to explain to sponsors why they should give is money for it. And while we discuss an explanation of linguistics that has mass appeal, others might take the challenge on finding a similar thing for computational linguistics.
Graphics taken from Open Clip Art Library, modified by Niels Ott.
5 Comments
I like the comparison to the dual nature of light, but I think you're right that it will just cause more confusion if the person doesn't know anything about physics.
You might also like to check out Marcus Dickinson's explanation of a paper on POS tagging targeted at a non-CL audience (if you haven't already seen it): http://jones.ling.indiana.edu/~mdickinson/papers/budapest.html
I was happy to come across your blog, by the way. It's always good to see new CL bloggers. I look forward to reading more!
And then people either think of programming languages (sigh) or of speech recognition.
(The latter supposedly is influenced by the fact that "language" and "speech" translate to the same word in German.)
That said, explaining linguistics is even harder than explaining computational linguistics. With CL, you can enumerate some applications. Like Google. Everyone knows Google, even the six-year-olds.
But linguistics? The common populace holds the assumption that "everyone knows how to speak," why should you then study language's properties? Isn't that solved already? When you start bringing in (mathematic) formalisms, people just think you're pulling their leg. Language has nothing to do with maths, after all.
I'd say the explanation of linguistics to the uninitiated is 'poorly understood.' We should write a research paper about it.
This fact, that my family doesn't know what I do, is a kind of evidence for the critical role we all need to play in explaining our field to the general public. After all, no one would ask a physicist, "So what is physics, anyway?" Similarly for a psychologist. This is in spite of the fact that a non-scientist has an equally vague idea of what physicists and psychologists work on as what linguists and computational linguists work on.
I start off with the simplest possible explanation, give a couple of phenomenon that have received some attention, and then try to end with some applications. Here is a sample spiel:
"Linguistics is the scientific study of language. There are a lot of things that we don't understand about language, so I'll just give you an example.
You know how when you listen to someone speaking in an unfamiliar language, it all kinda sounds like a blur, but when you listen to a familiar language, you hear it as a discrete sequence of words? There has to be something in your mind that helps you segment the speech stream into word-size units. You might think that it is because you recognize the words, but actually, it turns out that infants can segment speech before they have learned very many words at all. So one question that linguistics tries to answer is, how do infants do that?
Linguistics is partly a basic science, but there are lots of applications. For example, Google is trying to improve its search interface. One way they have done this is to detect when someone is asking a question, and try to answer it. But it takes a lot of work to get a computer to understand the meaning of a question. For example, consider what has to happen for the computer to answer these questions:
(1) What do skunks like to eat?
(2) What likes to eat skunks?
These questions both contain almost the same words, but the answers are completely different. That is because the question word (what) refers to the object in the first sentence, but the subject in the second. To answer these questions properly, Google needs to determine the grammatical role of the question word, which requires a pretty sophisticated understanding of English questions.
Another example of computational linguistics is machine translation, like when you're trying to read a website in Spanish, you can get a partial translation into English. So this is the kind of thing that we do in linguistics and computational linguistics."
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