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.

A relative clause contains a WH-phrase which moves and is adjoined to CP: The student who likes syntax is a cog-sci major. Our neighbor's dog, who the mailman was bit by, has been muzzled. The ...

Relative clauses are used to give additional information about a noun, such as a person, place or thing. Relative pronouns introduce a relative clause. They include who for people, that and which ...

Some common if questionable English usage may be technically wrong but just fine in real life, while other usage may depend ...