Dependency grammar The idea that syntactic structures reduce to binary relations was introduced by
Lucien Tesnière in 1959 within the framework of
dependency theory, which was further developed in the 1960s. Tesnière distinguished two structures that differ in the placement of the structurally governing element (
head):
centripetal structures, in which heads precede their
dependents, and
centrifugal structures, in which heads follow their dependents. Dependents here may include
complements,
adjuncts, and
specifiers.
Typology Joseph Greenberg, who worked in the field of
language typology, put forward an implicational theory of
word order, whereby: • If a language has VO (verb-before-object) ordering, then it will also have
prepositions (rather than postpositions), and genitives and adjectives will be placed after the noun they modify. • If a language has OV ordering, then it will also have postpositions, and genitives and adjectives will be placed before the noun they modify. The first set of properties make heads come at the start of their phrases, while the second set make heads come at the end. However, it has been claimed that many languages (such as
Basque) do not fulfill the above conditions, and that Greenberg's theory fails to predict the exceptions.
Fundamental Principle of Placement Winfred P. Lehmann, expanding upon Greenberg's theory, proposed a
Fundamental Principle of Placement (FPP) in 1973. The FPP states that the order of object and verb relative to each other in a language determines other features of that language's typology, beyond the features that Greenberg identified. Lehmann also believed that the subject is not a primary element of a sentence, and that the traditional six-order typology of languages should be reduced to just two, VO and OV, based on head-directionality alone. Thus, for example, SVO and VSO would be considered the same type in Lehmann's classification system.
Principles and parameters Noam Chomsky's
Principles and Parameters theory in the 1980s introduced the idea that a small number of innate principles are common to every human language (e.g. phrases are oriented around heads), and that these general principles are subject to parametric variation (e.g. the order of heads and other phrasal components may differ). In this theory, the dependency relation between heads, complements, specifiers, and adjuncts is regulated by
X-bar theory, proposed by Jackendoff in the 1970s. The complement is sister to the head, and they can be ordered in one of two ways. A head-complement order is called a
head-initial structure, while a complement-head order is called a
head-final structure. These are special cases of Tesnière's centripetal and centrifugal structures, since here only complements are considered, whereas Tesnière considered all types of dependents. In the principles and parameters theory, a head-directionality parameter is proposed as a way of
classifying languages. A language which has head-initial structures is considered to be a
head-initial language, and one which has head-final structures is considered to be a
head-final language. It is found, however, that very few, if any, languages are entirely one direction or the other. Linguists have come up with a number of theories to explain the inconsistencies, sometimes positing a more consistent
underlying order, with the phenomenon of phrasal
movement being used to explain the surface deviations.
Antisymmetry According to the
Antisymmetry theory proposed by
Richard S. Kayne, there is no head-directionality parameter as such: it is claimed that at an underlying level, all languages are head-initial. In fact, it is argued that all languages have the underlying order Specifier-Head-Complement. Deviations from this order are accounted for by different
syntactic movements applied by languages. Kayne argues that a theory that allows both directionalities would imply an absence of
asymmetries between languages, whereas in fact languages fail to be symmetrical in many respects. Kayne argues using the concept of a probe-goal search (based on the ideas of the
Minimalist program), whereby a
head acts as a probe and looks for a goal, namely its
complement. Kayne proposes that the direction of the probe-goal search must share the direction of language
parsing and production. Parsing and production proceed in a left-to-right direction: the beginning of sentence is heard or spoken first, and the end of the sentence is heard or spoken last. This implies (according to the theory) an ordering whereby probe comes before goal, i.e. head precedes complement. Some linguists have rejected the conclusions of the Antisymmetry approach. Some have pointed out that in predominantly head-final languages such as
Japanese and
Basque, the change from an underlying head-initial form to a largely head-final surface form would involve complex and massive leftward movement, which is not in accordance with the ideal of grammatical simplicity. Some take a "surface true" viewpoint: that analysis of head direction must take place at the level of
surface derivations, or even the
Phonetic Form (PF), i.e. the order in which sentences are pronounced in natural speech. This rejects the idea of an underlying ordering which is then subject to movement, as posited in Antisymmetry and in certain other approaches. It has been argued that a head parameter must only reside at PF, as it is unmaintainable in its original form as a structural parameter. Some linguists have provided evidence which may be taken to support Kayne's scheme, such as Lin, who considered Standard Chinese sentences with the
sentence-final particle . Certain restrictions on movement from within verb phrases preceding such a particle are found (if various other assumptions from the literature are accepted) to be consistent with the idea that the verb phrase has moved from its underlying position after its head (the particle here being taken as the head of an
aspect phrase). However, Takita (2009) observes that similar restrictions do not apply in Japanese, in spite of its surface head-final character, concluding that if Lin's assumptions are correct, then Japanese must be considered to be a true head-final language, contrary to the main tenet of Antisymmetry. More details about these arguments can be found in the
Antisymmetry article.
Gradient classification Some scholars, such as Tesnière, argue that there are no absolute head-initial or head-final languages. According to this approach, it is true that some languages have more head-initial or head-final elements than other languages do, but almost any language contains both head-initial and head-final elements. Therefore, rather than being classifiable into fixed categories, languages can be arranged on a
continuum with head-initial and head-final as the extremes, based on the frequency distribution of their
dependency directions. This view was supported in a study by Haitao Liu (2010), who investigated 20 languages using a dependency
treebank-based method. For instance, Japanese is close to the head-final end of the continuum, while English and German, which have mixed head-initial and head-final dependencies, are plotted in relatively intermediate positions on the continuum. Polinsky (2012) identified the following five head-directionality sub-types: • Rigid head-final languages, including
Japanese,
Korean and
Tamil; • Non-rigid head-final languages, including
Latin,
German,
Persian,
Basque,
Tsez and
Avar; • Clearly head-initial languages, including
Irish,
Malagasy,
Tongan and most
Mayan languages; • "SVO/head-initial" languages, including
Indonesian and
Yucatec Mayan; • "SVO sundry", including
English,
Russian, the
Romance languages and
Bantu languages. She identified a strong correlation between the head-directionality type of a language and the ratio of verbs to nouns in the lexical inventory. Languages with a scarcity of simple verbs tend to be rigidly head-final, as in the case of Japanese, whereas verb-rich languages tend to be head-initial languages. == See also ==