Phrase Structure Rules 1965 – 1986

Linguistic War

Not everyone agreed with Chomsky. During the 1960s and 1970s there was a so-called “Linguistics War” between those who thought syntax was most important and those who believed in the importance of semantics. The Chomskyan syntax group won and developed a theory in which syntax is relatively independent from semantics. Grammar, therefore, was to be central to understanding how human language ability works (at least for Chomsky’s followers). By understanding grammar, it was claimed, we could understand the mysterious workings of the human brain.

The 1960s and 1970s witnessed a “Linguistics War” between groups who believed syntax was most important and those who favoured semantics. The semantics group lost. The Chomskyans were free to develop their ideas about the unique human capacity for language, with grammar at the center. Photo. By Werner Co. [Public domain], via Wikimedia Commons
More Movement

With an Operator node that could be used to decide the type of sentence, it naturally made people think about more movement possibilities. So, for example, in the simple sentence below, we have invisible movement to the aux node.

As mentioned, it seems that we have invisible movement of the tense element ed to the aux node before the verb.

Now, maybe we can move some kind of tense element further in order to make a question sentence.

Now we have a longer visible movement operation to the Operator node in order to make the sentence into a question.

These mysterious movement operations became central to Chomsky’s ideas about language. While the idea that things are moving around in the grammar seemed a little strange, this could be explained as part of our unique, universal grammatical ability.

X-bar theory
The idea with X-bar theory was that ALL categories should have the same levels of structure. If we are born with this knowledge, it might make the task of learning a language easier.

The next important change concerned the categories employed in syntactic analysis. This movement was to become known as X-bar theory. This is sometimes written as X’ or with a line over the X. This just meant that all categories had (basically the same) levels of structure. X” was the highest level, X’ was the next, and X was the lowest level.

As you can see, with X-bar theory, ALL categories projected the same basic structure. A sentence was assumed to be an Inflectional Phrase (IP). The idea was that the old aux/tense node was projecting as a category carrying the inflectional properties of the verb.  Photo. By Xbarst1.jpg: Russky1802 derivative work: Maxdamantus (This file was derived from: Xbarst1.jpg:) [Public domain], via Wikimedia Commons
Remember our aux node? We might imagine that the inflectional properties of a verb (tense, aspect, etc.) move to this node for some reason. Now this category had to follow X-bar theory and project the same structure as the other categories. This became known as the Inflectional Phrase.

Here’s the old system with aux. X-bar theory gives this aux category full status as an inflectional phrase (IP).
Here’s the new way of doing the same thing. I projects as I’ and IP, just like the other categories.