Pro-drop parameter or Null subject parameter is the parameter which determines whether a language is a pro-drop language or not. A positive setting of the parameter allows an empty pro-element to be identified by its governor. This is the case in pro-drop languages.
Description
A term used in government-binding theory for a specification of the types of variation that a principle of grammar manifests among different languages. It is suggested that there are no rules of grammar in the traditional sense, but only principles which can take a slightly different form in different languages. For example, a head parameter specifies the positions of heads within phrases. The adjacency parameter of case theory specifies whether case assigners must be adjacent to their noun phrases. The pro-drop parameter determines whether the subject of a clause can be suppressed. Determining the parametric values for given languages is known as parameter-setting. The overall approach has been called the principles and parameterstheory ofuniversal grammar, and has since come to be applied outside of syntactic contexts, notably in characterizing phonological relations. Later versions of metrical phonology, for example, recognize a series of parameters governing the way metrical feet should be represented, such as quantity sensitivity and directionality. a parameter which determines whether the subject in declarative sentences may be deleted. Parameters vary in different languages within certain defined limits. Languages such as Italian and Arabic can have subject-less declarative sentences, e.g. Italian parla ‘he/she speaks/talks’, and are referred to as pro-drop languages. However, languages such as English, French and German do not typically omit the subject in declarative sentences. They are referred to as non-pro-drop languages, e.g.:
Subject
Verb
Italian
parla
pro-drop
Arabic
yatakalamu
pro-drop
English
he
speaks
non-pro-drop
French
il
parle
non-pro-drop
German
er
spricht
non-pro-drop
The term pro-drop is used because in the d-structure of the grammar, the empty subject position is filled by the element pro, e.g. pro parla The pro-drop parameter and other parameters of Universal Grammar have attracted the interest of researchers working in the fields of child language acquisition and language teaching. For example, the question has been raised: How do children ‘set’ a UG parameter to fit their particular language? Researchers in second language acquisition have investigated what happens if a parameter in the speaker's native language is different from that of their target language, making it necessary to ‘reset’ the parameter. This would happen, for example, in the acquisition of Spanish by speakers of non-pro-drop languages such as English and French. In GB, anyone of various putative universal statements permitting a specified degree of variation within languages. The idea is that anyone language selects just one of the small number of choices permitted by the theory of grammar. Examples include the Head Parameter, the Adjacency Parameter and the Pro-Drop Parameter. Notion in the theory of Universal Grammar and language acquisition. Parameters specify certain options that are not specified in UG. The values of parameters are not genetically fixed. Thus, language acquisition becomes a process of parameter setting. Linguistic diversity is characterized in terms of the values of parameters, for example the null subject parameter. Certain languages such as Italian and Spanish may have sentences with no overt subject, while other languages such as English must have an overt subject, even in cases in which this is nonreferential. Parameter theory, thus, provides an explanation for systematic syntactic variation between languages and imposes restrictions on the number of choices which the language learner has to make.
