The girl ,is only 10, can speak four languages… (non-defining relative clause)

NON-DEFINING RELATIVE CLAUSE

Relative clauses are used to give additional information about a noun (or pronoun) in a sentence. 

A non-defining relative clause gives extra information that is not crucial to the main meaning of the sentence. It provides additional details or comments about the noun, but the sentence would still make sense if the non-defining clause were removed. 

For example: "My sister, who lives in London, is coming to visit."

Forming Non-defining Relative Clauses:

1. Punctuation: Non-defining relative clauses are usually separated from the main clause by commas (or sometimes dashes). This punctuation helps to indicate that the information is extra and can be omitted without changing the essential meaning of the sentence.

2. Relative Pronouns: The relative pronouns used in non-defining relative clauses are 'who', 'whom', 'which', 'whose', and 'that'. 'Who' is used for people, 'which' is used for things, animals, or groups, 'whose' shows possession, and 'whom' is a more formal version of 'who' used for people.

3. Verb Usage: The verb in a non-defining relative clause agrees with the noun it refers to. 

For example, "The book, which was written in 1900, is a classic."

Examples:

1. My father, who is a doctor, just retired.

   - The non-defining clause "who is a doctor" provides additional information about "my father" but can be removed without affecting the main meaning of the sentence.

2. The Louvre Museum, which is located in Paris, is famous for its art collection.

   - The non-defining clause "which is located in Paris" gives extra information about "The Louvre Museum" but doesn't change the core meaning of the sentence.

3. Our new house, whose garden is beautifully landscaped, is a wonderful place to live.

   - The non-defining clause "whose garden is beautifully landscaped" adds detail to "our new house" but isn't essential to the sentence's main point.

4. Jane, whom I met at the conference, is a talented pianist.

   - The non-defining clause "whom I met at the conference" provides additional information about "Jane" but can be omitted without altering the main idea.