Module 2 LectureWhat do we know when we know a language?Module 2 LectureWhat do we know when we know a language? In the reading for Module 2, Chomsky describes a machine for generating sentences. This machine to some extent mimics the way we write sentences from left to right one word at atime, or speak sentences from beginning to end one word at a time. Each word produced is a single state of the machine. Before it proceeds to the next state (that is, the next word), it consults a dictionary available to it for the list of possible words that can follow the previousstate (that is, previous word). When it finds one it moves on to the next state. For example, the machine can have the following output:1. the --> man --> thinks --> about --> his --> dogThus, man is a noun that can follow the, thinks is a verb that can follow the noun man, about is a preposition that can follow think, etc.The machine would not produce (2).2. *the --> man --> thinks --> John (an asterisk marks the sentence as ungrammatical)That is, the noun John cannot follow the verb think unless John is the beginning of another sentence as in (3).3. The man thinks John is sleeping.The machine, operating one word at a time cannot see beyond John. Since John is not a possible next state after think, the machine will never generate (3). The machine, therefore, cannot generate the set of English sentences. If the speaker/hearer also produced or understood sentences one word at a time from left to right, then it too could not generate the set of English sentences. Thus, the common sense observation that sentences are constructed from left to right, one word at a time, cannot be a correct account of grammatical knowledge.(3) is an answer to the question in (4), which can also not be produced by the machine.4. Who does the man think is sleeping?In (4) the verb think is followed by the verb is which in a word-by-word sequence is unacceptable at that point. In a later module we will discuss questions that begin with awh-word like who. For now, we can assume that who is a question about the subject of is sleeping as in the following structure:5. does the man think [John/who] is sleepingSince the machine can only know the state it is in when it chooses the next state, it cannot know that in (4) the word who occurs several states previous to think and signals a gap following think that refers to the subject of is sleeping. A speaker of English knows thatthere is a relationship between the question word who at the beginning of the sentence andthe missing subject between think and is sleeping. We will refer to this connection as displaced reference. The speaker’s internalized grammar allows for displaced reference of this sort. The machine that proceeds from one state to the next cannot accommodate displaced reference, since it cannot look back, and thus it fails to generate the set of possible English sentences. Similarly, the common sense notion that speakers produce sentences one word at a time from left to right like the machine must also be wrong. Instead sentence production and understanding must have a way of accommodating displaced reference. The internalized grammar must have a mechanism to relate question words like who to gaps in the sentence it heads. In sentence (4), who is pronounced at the beginning of the sentence, but it is understood as referring to the empty position before is sleeping.Once again we see that common sense observations about language cannot account for thefacts. A scientific account must delve deeper than simple observation. In the case at hand, itappears that sentences must have structure that is not simply linear. Furthermore, this nonlinear structure must relate parts of the sentence that are distant from one another. In sentence (4), four words come between who and the missing subject of is sleeping. In sentence (6), there are six words between these items.6. Who does Harry believe the man thinks __ is sleeping? (Compare: Harry believes the manthinks John is sleeping.)In sentence (7) there are eight words between these items.7. Who does John know Harry believes the man thinks __ is sleeping? (Compare: John knows Harry believes the man thinks John is sleeping.)The distance between who and the gap of the displaced subject of is sleeping can be made even greater by substituting the judge for John and the lawyer for Harry in (7). As the distance governing the displaced reference becomes longer it may create memory problemsfor an actual speaker, but the grammar should allow for an indefinitely long distance. The internalized mechanism for generating sentences can be thought of as the grammar of an ideal speaker/hearer, one without memory limitations, as we have already seen with indefinitely long sentences in Module 1. Since actual speakers will vary in the limitations memory might play, a scientific account can abstract away from such variation if it is an irrelevant complicating factor.Goal: internal mechanism of sentence construction in the speaker/hearer.Displaced reference, as described above, is a feature specific to human languages. It is not found in the communications systems of other animals. For that reason it is taken to be a property of mind specific to human language and of special interest in a course on language and