24 July 2008

Last week I learned...

  • When volcanic eruptions created the island of Ferdinandea in 1831, it was quickly claimed by Italy, France, the UK, and Spain. While they were arguing, the little island eroded away.

  • How to put this? Language isn't what I thought it was. (This definitely falls into the category of thought-provoking stuff I won't pretend to understand.)

    A little background. Before your third birthday, you subconsciously achieved a thorough familiarity with the grammar of the language spoken in your home. Never mind that you said I've sawn instead of I've seen. That's small stuff. You knew when to use the and when to use a. You knew which of they run and they runs was right, that big green circle sounds better than green big circle, how to figure out what it means in context, and much more. You will never have conscious understanding of all the syntactic rules you already had subconsciously at three. No one does. Not even people who make a career out of studying exactly that.

    Linguists aren't dumb. Why is it that toddlers are able to do this amazing thing that all the linguists in the world, given several decades to work, can't do?

    Beats me, but there's something else kids do that's even more amazing. They invent grammar.

    I'm tempted to block-quote about a page out of this book I'm reading (Foundations of Language by Ray Jackendoff). It's fascinating stuff. “Derek Bickerton documents in detail that children of a pidgin-speaking community do not grow up speaking the pidgin, but rather use the pidgin as raw material for a grammatically much richer system called a ‘creole’.” If adults could do that, there wouldn't be a pidgin phase. The kids do it. Where does that come from?

    Communities can exist for millenia without developing writing. They don't go without grammatically complex spoken language. Hmmm.

    Even better, there's a school for the deaf in Nicaragua where the kids, unprompted, made up their own sign language. “Besides offering the wonder of a whole language coming out of nowhere, Nicaraguan Sign Language sheds some light on questions about creole. Evidently a community is necessary for language creation, but a common stock of pre-existing raw material is not.” I always assumed the syntax of a language like English comes together incrementally, over thousands of years. Shows what I know. It was probably invented in a single generation.

  • Parahã, a language spoken by a few hundred people in Brazil, contains, according to Wikipedia, “two very rare sounds, [ɺ͡ɺ̼] and [t͡ʙ̥]”. In case you don't have the fonts I do, that first one looks like two upside-down lowercase rs with a squiggle underneath like a bird in flight, and a arc over the top; and the second one looks like tB with a dot under the B and an arc over the top. I wonder how they're pronounced.

  • In the version of g++ that ships on the Mac these days (GCC 4.0.1), you can get the old-school SGI STL hash_map container by doing #include <ext/hash_map> and using __gcc_cxx::hash_map;. But the GCC guys have already replaced the hash_ containers with newer standards-track containers, unordered_map and friends, which you can get in a more recent libstdc++.

  • In C++, a class's private members are not entirely hidden from code that uses the class. It's possible for public names to collide with private names. For example:

        class A { private: void f(); };  // This method is private, but its name matters...
        class B { public:  void f(); };  // ...because it'll conflict with this one.
        class C : public A, public B {};
        C().f();  // Error: request for member ‘f’ is ambiguous.

    Leaky abstractions make me sad. This doesn't seem to come up often in practice, but I think it's one reason STL implementations tend to contain lots of extra underscores. Another reason for that, as Blake Kaplan pointed out to me, is that a standard C++ program can do:

    #define n 3
    #include <vector>

    and the headers should be able to cope with that.

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