Relativizers

Relativizers are morphemes or words that introduce relative clauses and link them to a noun phrase in the main clause. They serve to identify or restrict the antecedent by describing a property or relation expressed in the relative clause. In many languages, a relativizer is realized as a relative pronoun (who, whom, which, that), a relative adverb (where, when), or as a dedicated subordinator or clitic. Some languages use a nominalizer or a different marker within the relative clause rather than a separate pronoun.

In English, relative clauses are usually postnominal. The book that I bought is on the shelf. The person who/that called is waiting. The city where I grew up has changed. Relative pronouns mark the grammatical role of the gap inside the clause (who for people, which/that for things). The relative marker can often be omitted in restrictive clauses: The book I bought. Prepositions can be stranded or pied-piped: The book to which I spoke, or The book that I spoke to.

Typologically, languages vary in where the relative clause is located (head-external languages place the RC after the head; head-internal languages place the RC before the head), in whether the relative marker is overt or zero, and in whether resumptive pronouns occur inside the RC. The structure can also interact with island constraints and binding, affecting which antecedents are acceptable.

Relativizers are a central part of grammar that enables embedding and linking of clauses to create complex noun phrases and to express descriptive relationships within discourse.