| Grammar | Languages | Automaton | Production rules (constraints) |
|---|---|---|---|
| Type-0 | Recursively enumerable | Turing machine |  (no restrictions) |
| Type-1 | Context-sensitive | Linear-bounded non-deterministic Turing machine |  |
| Type-2 | Context-free | Non-deterministic pushdown automaton |  |
| Type-3 | Regular | Finite state automaton |  and  |
0型語言是限定條件最少的語言, 也是最基本的語言, 其他類型的語言都是他的子集.
喬木斯基認爲迭代(recursive)也是人類語言的基本特徵之一.(不清楚喬木斯基文法有沒有包括人類語言),比如:
我是一隻大灰狼
我認爲我是一隻大灰狼
"我是一隻大灰狼"這個句子是第二個句子的一部分(我在這裏終於明白0型文法的含義了 :)).
沒有迭代特性的語言就只能表達有限的信息.
贏得諾貝爾經濟學獎的Herbert Simon在1962年的文章<The Architecture of Complexity>也指出迭代的結構是信息處理的基本結構, 當然包括語言的處理. 計數就是一種迭代: 1, 2,...n...
或許所有人類思考的有迭代的特性, 但並不是所有的語言都有迭代的特性. Daniel L. Everett 講了這個. 他發現了一個沒有迭代特性的語言: 亞馬遜森林中Pirahã人的語言.他舉了個例子, 我們表達:
張三的弟弟有座的房子
但這個特殊的人羣說:
張三有一個弟弟, 他弟弟有個房子
這個語言系統也確實沒有計數的表達.
Pirahã人相信他們經驗世界的事情: 拿出證據來.比如作者曾給他們講聖經的故事, 但似乎對那些人沒有什麼影響. 終於有個Pirahã人點破了他: "耶酥是什麼顏色的? 他有多高?他什麼時候告訴你這些事情的?.." 作者當然不知道. Pirahã人回答他: 那你爲什麼告訴我們這個?(真是實事求是!) 一個第一次座飛機的piraha人對飛機, 對天空也沒有什麼覺得新奇的, 那不是他興趣內的世界.
不由得驚歎世界真是無奇不有: 因爲我們不認識, 所以覺得奇怪.
也可以看出這羣人生活的很孤立, 並且很難自己發展, 也不能接受外界的輸入, 不說會沒落, 他們至少無法走出亞馬遜. 一個和外界有交流, 有擴展能力的系統才能發展.
但這些人有傳說中的隱士的味道: 不爲外物所動. 也許, 那就是他們的幸福所在吧. 希望地震中的同胞能更多的被拯救出來, 享受他們的幸福.
全文在這裏:RECURSION AND HUMAN THOUGHT: WHY THE PIRAHÃ DON'T HAVE NUMBERS A Talk With Daniel L. Everett : Dan Everett believes that Pirahã undermines Noam Chomsky’s idea of a universal grammar.
還有一些有趣的例子:
"I sat with a Pirahã once and he said, what does your god do? What does he do? And I said, well, he made the stars, and he made the Earth. And I asked, what do you say? He said, well, you know, nobody made these things, they just always were here.
The first time I took a Pirahã on an airplane, I got a similar reaction. I was flying a man out for health reasons; he had a niece who needed surgery and he was accompanying her. We're flying above the clouds, and I know that he's never seen clouds from the top before, so I point down and I say, those are clouds down there. Uh huh. He was completely uninterested; he acted like he flew in planes every day. The Pirahã are not that curious about what we have. They haven't shown interest in a number of things that other indigenous groups, even Amazonian groups, that have come out and had contact with in civilization for the first time are curious about. The Pirahã have been in regular contact for a couple of hundred years now, and they have assimilated almost nothing. It's very unusual."
The reason that I believe that the Pirahã are like this is because of the strong cultural values that they have—a series of cultural values. One principle is immediacy of experience; they aren't interested in things if they don't know the history behind them. If they haven't seen it done. But there's also just a strong conservative core to the culture; they don't change, and they don't change the environment around them much either. They don't make canoes. They live on the river, and they depend on canoes for their daily existence—someone's always fishing, someone's always crossing the river to hunt and gather—but they don't make canoes. If there are no Brazilian canoes, they'll take the bark off a tree and just sit in that and paddle across. And that's only good for one or two uses.
I brought in a Brazilian canoe master, and spent days with them and him in the jungle; we selected the wood, and made a dugout canoe. The Pirahã did all the labor—so they knew how to make a canoe, and I gave them the tools—but they came to me and they said, we need you to buy us another canoe. I said, well we have the tools now, and you guys can make canoes. But they said, Pirahã don't make canoes. And that was the end of it. They never made a canoe like the Brazilians, even though I know that some of them have the skills to do that.
"The crucial thing is that the Pirahã have not borrowed any numbers—and they want to learn to count. They asked me to give them classes in Brazilian numbers, so for eight months I spent an hour every night trying to teach them how to count. And it never got anywhere, except for a few of the children. Some of the children learned to do reasonably well, but as soon as anybody started to perform well, they were sent away from the classes.
It also doesn't explain their lack of color words, the simplest kinship system that's ever been documented, the lack of recursion, and the lack of quantifiers, and all of these other properties.
I remember one time sitting in a hut with the Pirahã and they came and they said, we understand that you want to tell us about Jesus and that Jesus tells us that we should live certain ways."