In linguistics, a relativizer (abbreviated ) is a type of conjunction that introduces a relative clause. For example, in English, the conjunction that may be considered a relativizer in a sentence such as "I have one that you can use." Relativizers do not appear, at least overtly, in all languages; even in languages that do have overt or pronounced relativizers, they do not necessarily appear all of the time. For these reasons it has been suggested that in some cases, a "zero relativizer" may be present, meaning that a relativizer is implied in the grammar but is not actually realized in speech or writing. For example, the word that can be omitted in the above English example, producing "I have one you can use", using (on this analysis) a zero relativizer.
Analysis
Since as far back as 1712, people have written about relativizers and what functions they have. They have been classified as conjunctions in earlier times, and have later been referred to as clause markers. They are known today as relativizers. Despite an agreement in nomenclature, there are multiple analyses which attempt to account for the grammatical function and distribution of relativizers.
Promotional analysis
The promotional analysis is a transformational analysis from 1973 depicting relative clauses in English, and how relative pronouns are introduced into the embedded clause. This analysis assumes that there is no overt head noun in the deep structure of the main clause. In order to form a relative construction, the noun phrase from the embedded clause is promoted to the empty head of the noun phrase of the main clause. From there, a corresponding relative pronoun leaves a trace in the space of the vacated noun phrase in the embedded clause. For example:
Matching analysis
The Matching Analysis is another type of transformational analysis from the 1970s, which was in competition with the Promotional Analysis at that time. In this analysis the relative pronoun is introduced into the embedded clause by corresponding or matching to the head noun in the main clause. This is done by taking the noun phrase from the embedded sentence in the deep structure that matches the head noun in the noun phrase of the main clause, and replacing it with a relative pronoun. The relative pronoun thus co-references the head noun in the main clause. Finally, the relative pronoun is moved to the clause-initial position. For example:
Ouhallian analysis
There are two separate phrasal heads that relativizers can occupy. Cross-linguistically, relativizers may occupy either the head of a complementizer phrase (C-Type Relativizer) or the head of a determiner phrase (D-Type Relativizer). C-Type Relativizers can introduce a relative clause as an argument of a noun phrase, or they can introduce a relative clause as an argument of a verb phrase. D-Type Relativizers may only introduce a relative clause as an argument of a noun phrase. English is a language which uses a C-Type Relativizer, that, as a part of its relativization strategy because "that" can introduce a relative clause as either the argument to a Noun Phrase or the argument to a Complementizer Phrase. The following examples from English shows the same morpheme being used in both syntactic contexts.
Conversely, Arabic uses two phonologically distinct morphemes to account for these syntactic phenomena. In the same sentences in a D-Type language like Arabic, each example would employ the use of a different morpheme as shown in examples 1 & 2. In Classical and Standard Arabic, the D-Type relativizer declines according to the gender and number of the noun, but the C-Type does not do so (according to the verb).
1) paris lli bħibba
Paris RM I.love.it
The Paris that I love
2) xabbaret-na laila ʔenno l-mmaslin mʔadrabiin
told-us laila that the-actors on.strike
Laila told us that the actors are on strike.
In modern English
There are three types of relativizers used in English to introduce relative clauses: zero or null relativizers, wh-relativizers, and the that-relativizer.