An essential relative clause provides necessary, defining information about the noun. On the other hand, non‐ essential relative clauses provide additional, non‐necessary information about the noun.

Relative pronouns close relative pronounA relative pronoun is a word used to link two parts of a sentence together when referring back to something mentioned at the start. are used to link phrases ...

Relative clauses are bound clauses that modify NPs and occasionally CPs. The former are adjoined to NPs. A relative clause contains a WH-phrase which moves and is adjoined to CP: The student who likes ...