X-bar theory

Revision as of 16:26, 20 January 2010

Syntax is the study of the principles and rules for constructing sentences in natural languages.

X-bar theory

The syntactic framework of the UNLarium derives from the X-bar theory ^[1], which postulates that all human languages share certain structural similarities, including the same underlying syntactic structure, whose abstract configuration is depicted in the diagram below:

    XP
   / \
spec  XB
     / \
    XB  adjunct
   / \
  X   comp
  |
head

In the above:

• X is the head, the nucleus or the source of the whole syntactic structure, which is actually derived (or projected) out of it.
• comp (i.e., complement) is an internal argument, i.e., a word, phrase or clause which is necessary to the head to complete its meaning (e.g., objects of transitive verbs)
• adjunct is a word, phrase or clause which modifies the head but which is not syntactically required by it (adjuncts are expected to be extranuclear, i.e., removing an adjunct would leave a grammatically well-formed sentence)
• spec (i.e., specifier) is an external argument, i.e., a word, phrase or clause which qualifies (determines) the head
• XB (X-bar) is the general name for any of the intermediate projections derived from X
• XP (X-bar-bar, X-double-bar, X-phrase) is the maximal projection of X.

A key assumption of X-bar theory is that branching is always binary, if it occurs. This means that specifiers, complements and adjuncts are optional and that there can be as many XBs as necessary:

  XP
  |
  XB
  |
 head

   XP
  /  \ 
spec XB
     |
    head

    XP
    |  
    XB
   /  \ 
head  comp 

    XP
    |  
    XB
   /  \ 
head  adjt 

   XP
  /  \  
spec  XB
     /  \ 
  head  adjt 

    XP
   / \
spec  XB
     / \
    XB  comp
   / \
  X   comp
  |
head

    XP
   / \
spec  XB
     / \
    XB adjt
   / \
  XB  comp
 / \
X   comp
|
head

The order of the constituents (specifiers, complements and adjuncts) is subject to language specific parametrization and may vary:

    XP
    |  
    XB
   /  \ 
head  comp 

    XP
    |  
    XB
   /  \ 
comp  head 

    XP
    |  
    XB
   /  \ 
head  adjt 

    XP
    |  
    XB
   /  \ 
adjt head 

Constituents

Heads

In the UNLarium approach to the X-bar theory, the heads, which should replace the letter X, may be occupied by the following categories ^[2]

• N = nouns and nominals: personal pronouns, demonstrative pronouns, nominalizations, etc
• V = verbs
• J = adjectives
• A = adverbs
• P = prepositions
• D = determiners: articles, demonstrative determiners, possessive determiners, quantifiers
• I = auxiliary verbs
• C = conjunction

The heads define the nature of the phrase structures, thus:

• N is the head of the Noun Phrase (NP)
• V is the head of the Verbal Phrase (VP)
• J is the head of the Adjectival Phrase (JP)
• A is the head of the Adverbial Phrase (AP)
• P is the head of the Prepositional Phrase (PP)
• D is the head of the Determiner Phrase (DP)
• I is the head of the Inflectional Phrase (IP)
• C is the head of the Complementizer Phrase (CP)

Specifiers

Specifiers are used to narrow the meaning intended by the head:

• articles: the (book), a (book), etc.
• possessive determiners: my (book), your (book), etc.
• demonstrative determiners: this (book), that (book), etc.
• quantifiers: no (answer), every (hour), etc.
• intensifiers (emphasizers, amplifiers, downtoners): very (expensive), quite (well), nearly (under), kind of (like), etc.
• frequency adverbs: always (go), never (go), usually (go), etc.
• negative adverbs: not (go)

Complements

Complements are used to complete the meaning intended by the head:

• direct objects: (do) something, (give) something
• indirect objects: (laugh at) something, (give to) someone
• complement of deverbals (i.e., nouns deriving from verbs): (construction of) the city, (arrival of) Peter
• complement of adjectives: (loyal) to the queen, (interested) in Chemistry
• complement of adverbs: (contrarily) to popular belief, (independently) from her
• complement of prepositions: (under) the table, (after) today
• complement of conjunctions: (and) Peter, (I don't know if) he'll come

Adjuncts

Adjuncts are used to modify the meaning intended by the head:

• adjectives: beautiful (table)
• manner adverbs: speak (slowly)
• prepositional phrases: (table) of wood

etc.

Phrases

Specifiers, complements and adjuncts are themselves complex syntactic structures (XPs) which are combined to form the sentence structure:

     NP
     |
     NB
     |
     N
     |
<b>construction</b>

     NP
   /    \  
spec     NB
 |        |
 DP       N
 |        |
 DB  construction
 |
 D
 |
the

       NP
    /     \  
spec        NB
 |        /     \
 DP    adjt      N
 |      |        |
 DB     JP  construction
 |      |
 D      JB
 |      |
the     J
        |
       fateful

         NP
    /         \  
spec           NB
 |         /        \
 DP    adjt          NB
 |      |          /     \ 
 DB     JP       N       comp
 |      |        |         |
 D      JB  construction   PP
 |      |                  |
the     J                  PB
        |                /    \
       fateful         P      comp
                       |        |       
                      of        NP
                                |
                                NB
                                |
                                N
                                |
                               Babel

References

1. ↑ Chomsky, Noam (1970). Remarks on nominalization. In: R. Jacobs and P. Rosenbaum (eds.) Reading in English Transformational Grammar, 184-221. Waltham: Ginn.
2. ↑ In the X-bar theory, differently from the UNLarium approach, adverbs are subsumed by prepositions and are not considered to be an independent lexical category.