What else do you know about syntax ?

Syntactic knowledge goes beyond being able to decide which strings are grammatical and which are not. it accounts for the double meaning, ar ambiguity, of expressions such as the one illustrated in the cartoon above. The humour of the cartoon depends on the ambiguity of the phrase syntactic buffalo hides, which can mean 'buffalo hides that are synthetic', or 'hides of synthetic buffalo'. This example illustrates that within a phrase, certain words are grouped together. Sentences have structure as well as word order. The word in the phrase synthetic buffalo hides can be grouped in two ways. when we group them like this  :

synthetic (buffalo hides)

we get the first meaning. when we group them like this  :

(synthetic buffalo) hides

we get the second meaning.
The rules of syntax allow both of these groupings, which is way the expression is ambiguous. The two structures may also be illustrated by the following diagrams  :

Many sentence exhibit such as ambiguities, often leading to humorous results, consider the following two sentences, which appeared in classified ads  :

For sale : an antique desk suitable for lady with thick legs and large drawers.
We will oil your sewing machine and adjust tension in your home for $10.00.

In the first ad, the humorous reading comes from the grouping :(for lady with thick legs and large drawers) as opposed to the intended : (for lady) (with thick legs and large drawers) where the legs and drawers belong the desk. the second case is similar.
Because these ambiguities are a result of different structures, they are instances of structural ambiguity. Contrast these sentences with  :
This make you smart.

The two interpretation of this sentence are due to the two meanings of smart 'clever' or 'to experience a burning sensation'.

Syntactic knowledge also enables us to determine the grammatical relations in a sentence, such as subject and direct object, and how they are to be understood. consider the following sentences  :

1. Mary hired Bill.
2. Bill hired Mary.
3. Bill was hired by Mary.

In (1) Mary is the subject and is understood to be the employer who did the hiring. Bill is the direct object and is understood to be employee. In (2) Bill is the subject and mary is the direct object and, as we would expect, the meaning changes so that we understand Bill to be Mary's employer. In (3) the grammatical relationship are the same as in (2), but we understand it to have the same meaning as (1), despite the structural differences between (1) and (3).

Syntactic rules reveal the grammatical relations between the words of a sentence and tell us when structural differences result in meaning differences and and when they do not we see that grammatical relations, such as subject and direct object, do not always tell us 'who does what whom' since in (1) and (2) the grammatical subject is the 'who' but in the (3) the subject is 'whom'.

The syntactic rules permit speaker to produce and understand an unlimited number of sentences never produced of heard before, the creative aspect of language use.
Thus, the syntactic rules of grammar must at last account for  :

1. The grammaticality of sentences
2. word order
3. structural ambiguity
4. grammatical relations
5. whether different structures have differing meanings or the same meaning
6. the creative aspect of language

A major goal of linguistics is to show clearly and explicitly how syntactic rules account for this knowledge. A theory of grammar must provide a complete characterisation of what speakers implicitly know about their language.