The Language Instinct: How the Mind Creates Language (17 page)

Now the story begins to get interesting. You must have noticed that noun phrases and verb phrases have a lot in common: (1) a head, which gives the phrase its name and determines what it is about, (2) some role-players, which are grouped with the head inside a subphrase (the N-bar or V-bar), (3) modifiers, which appear outside the N- or V-bar, and (4) a subject. The orderings inside a noun phrase and inside a verb phrase are the same: the noun comes before its role-players
(the destruction of the hotel room
, not
the of the hotel room destruction)
, and the verb comes before
its
role-players
(to destroy the hotel room
, not
to the hotel room destroy)
. The modifiers go to the right in both cases, the subject to the left. It seems as if there is a standard design to the two phrases.

In fact, the design pops up all over the place. Take, for example, the prepositional phrase (PP)
in the hotel
. It has a head, the preposition
in
, which means something like “interior region,” and then a role, the thing whose interior region is being picked out, in this case a hotel. And the same goes for the adjective phrase (AP): in
afraid of the wolf
, the head adjective,
afraid
, occurs before its role-player, the source of the fear.

With this common design, there is no need to write out a long list of rules to capture what is inside a speaker’s head. There may be just one pair of super-rules for the entire language, where the distinctions among nouns, verbs, prepositions, and adjectives are collapsed and all four are specified with a variable like “X.” Since a phrase just inherits the properties of its head (
a tall man
is a kind of
man
), it’s redundant to call a phrase headed by a noun a “noun phrase”—we could just call it an “X phrase,” since the nounhood of the head noun, like the manhood of the head noun and all the other information in the head noun, percolates up to characterize the whole phrase. Here is what the super-rules look like (as before, focus on the summary of the rule, not the rule itself):

Just plug in noun, verb, adjective, or preposition for X, Y, and Z, and you have the actual phrase structure rules that spell the phrases. This streamlined version of phrase structure is called “the X-bar theory.”

This general blueprint for phrases extends even farther, to other languages. In English, the head of a phrase comes before its role-players. In many languages, it is the other way around—but it is the other way around across the board, across all the kinds of phrases in the language. For example, in Japanese, the verb comes
after
its object, not before: they say
Kenji sushi ate
, not
Kenji ate sushi
. The preposition comes after its noun phrase:
Kenji to
, not
to Kenji
(so they are actually called “postpositions”). The adjective comes after its complement:
Kenji than taller
, not
taller than Kenji
. Even the words marking questions are flipped: they say, roughly,
Kenji eat did?
, not
Did Kenji eat?
Japanese and English are looking-glass versions of each other. And such consistency has been found in scores of languages: if a language has the verb before the object, as in English, it will also have prepositions; if it has the verb after the object, as in Japanese, it will have postpositions.

This is a remarkable discovery. It means that the super-rules suffice not only for all phrases in English but for all phrases in all languages, with one modification: removing the left-to-right order from each super-rule. The trees become mobiles. One of the rules would say:

To get English, one appends a single bit of information saying that the order within an X-bar is “head-first.” To get Japanese, that bit of information would say that the order is “head-last.” Similarly, the other super-rule (the one for phrases) can be distilled so that left-to-right order boils away, and an ordered phrase in a particular language can be reconstituted by adding back either “X-bar-first” or “X-bar-last.” The piece of information that makes one language different from another is called a parameter.

In fact, the super-rule is beginning to look less like an exact blueprint for a particular phrase and more like a general guideline or principle for what phrases must look like. The principle is usable only after you combine it with a language’s particular setting for the order parameter. This general conception of grammar, first proposed by Chomsky, is called the “principles and parameters” theory.

Chomsky suggests that the unordered super-rules (principles) are universal and innate, and that when children learn a particular language, they do not have to learn a long list of rules, because they were born knowing the super-rules. All they have to learn is whether their particular language has the parameter value head-first, as in English, or head-last, as in Japanese. They can do that merely by noticing whether a verb comes before or after its object in any sentence in their parents’ speech. If the verb comes before the object, as in
Eat your spinach!
, the child concludes that the language is head-first; if it comes after, as in
Your spinach eat!
, the child concludes that the language is head-last. Huge chunks of grammar are then available to the child, all at once, as if the child were merely flipping a switch to one of two possible positions. If this theory of language learning is true, it would help solve the mystery of how children’s grammar explodes into adultlike complexity in so short a time. They are not acquiring dozens or hundreds of rules; they are just setting a few mental switches.

The principles and parameters of phrase structure specify only what kinds of ingredients may go into a phrase in what order. They do not spell out any particular phrase. Left to themselves, they would run amok and produce all kinds of mischief. Take a look at the following sentences, which all conform to the principles or super-rules. The ones I have marked with an asterisk do not sound right.

It must be the verb’s fault. Some verbs, like
dine
, refuse to appear in the company of a direct object noun phrase. Others, like
devour
, won’t appear without one. This is true even though
dine
and
devour
are very close in meaning, both being ways of eating. You may dimly recall from grammar lessons that verbs like
dine
are called “intransitive” and verbs like
devour
are called “transitive.” But verbs come in many flavors, not just these two. The verb
put
is not content unless it has both an object NP
(the car)
and a prepositional phrase
(in the garage)
. The verb
allege
requires an embedded sentence
(that Bill is a liar)
and nothing else.