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Linguistique MM » Grammar Tips: Essential and Nonessential Clauses

Grammar Tips: Essential and Nonessential Clauses


When faced with a clause, the question invariably arises as to whether it should be surrounded by commas or not. But how can you tell?

We therefore take a look at the somewhat lesser-known concepts of essential and nonessential clauses. What's the difference, and when should a comma be used?

In this blog post, we demystify essential and nonessential clauses, highlighting the differences and clarifying beyond any doubt when to surround the clause with commas. Let's get started!


The Difference Between Essential and Nonessential Clauses

To identify when a comma is needed, it's essential to know how to differentiate between essential and nonessential clauses. It all depends on the context! So, without further ado, let's get to the heart of the matter.

  1. Essential Clauses

As their name suggests, essential clauses are essential to determine the noun that accompanies them. Their presence near the noun makes it possible to know precisely which noun is being referred to, and this is what makes them essential. To find out whether a clause is essential, simply ask yourself whether the clause identifies the noun in question. 

Examples

Your sister who is ill didn't go to school. (In the case of more than one sister, the clause “who is ill” is an essential clause, since it determines which sister didn't go to school. We're talking here about the one who's sick, not another sister.)

My friend whose electricity is out is coming home to eat. (In this example, the clause “whose electricity is out” is used to determine which friend is being referred to, so the clause is essential.)

My cat whose leg is broken has to go to the vet. (If there are several cats, the clause “whose leg is broken” is used to determine which cat must go to the vet among several cats, making it essential.)

  1. Nonessential Clauses

Nonessential clauses, on the other hand, are nonessentialin identifying the noun they refer to. Nonessential clauses add additional information to the noun, without providing the information needed to determine which noun it is. The information added can be very important, but if it doesn't identify the noun, the clause is still nonessential.

Examples

Annie, who has gone to school, should do her homework. (Here, the clause “who has gone to school” adds information about Annie. Since we already know that the subject in question is Annie, the clause is nonessential.) 

Your wife, who's back from the grocery store, is going to eat at home. (The clause adds information, but we already know that the subject is “your wife”. The clause is therefore nonessential.)

My cat, who has a broken leg, has to go to the vet. (If there's only one cat, the noun complement “who has a broken leg” adds information about the cat, but we already know which cat it is, since there's only one cat. In this case, the clause is nonessential.)


The Importance of Context

When distinguishing between essential and nonessential clauses, context makes all the difference. Indeed, the same sentence may have an essential or nonessential clause, depending on the circumstances. So it's important to ask whether the noun itself contains the information required to know which noun it is (nonessential clause), or whether the clause is used to determine which noun it is (essential clause). 


When Should Commas Be Used?

Now that you know how to tell the difference between essential and nonessential clauses, you've got all you need to know when to use commas. 

Indeed, it's vital to surround nonessential clauses with commas. On the other hand, commas should never be used when the clause is essential. It's as simple as this!


In Brief

Essential clauses allow the noun to be determined, while nonessential clauses add additional information to the noun. Nonessential clauses should be surrounded by commas, while essential clauses should not. 

The Linguistique MM team hopes to have helped demystify essential and nonessential clauses. If you need help proofreading your English or French texts, feel free to contact us directly to get a free quote for the revision of your texts!

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