Exploring Non-Defining Relative Clauses

Non-defining relative clauses offer additional information without identifying the subject or object of the sentence. An example is 'David's mother, who was born in Mexico, is my sister's Spanish teacher,' where the clause adds information about David's mother but is not necessary for understanding who she is. Unlike defining clauses, non-defining clauses cannot start with 'that' and must be set apart by commas in written English. They can be omitted without losing the core meaning of the sentence, as seen in the example where 'David's mother is my sister's Spanish teacher' remains clear on its own.