A parenthetical expression is simply a word or string of words which contains relevant yet non-essential information. In order to let the reader know that this information is not essential to the sentence (it is non-restrictive), it is important that the parenthetical expression be punctuated properly. Let’s look at an example of how parenthetical expressions work in a sentence:

The tortoise, as far as we know, has been on earth for thousands of years

The parenthetical expression as far as we know conveys to the reader that this statement is not a concrete fact. However, the grammatical meaning of the sentence would not be affected by the parenthetical expression’s removal.

Other phrases commonly used as parenthetical expressions include the following: however, nevertheless, in fact, therefore, for instance, consequently, for example, accordingly, moreover, hence.

Since all parenthetical expressions are non-restrictive, they should be set off with punctuation. One of the best ways to set them off is with commas. This punctuation shows that the information contained within the set of commas is non-essential, yet still related in context.

Example 1: Use commas to separate parenthetical expressions which occur at the beginning or in the middle of a sentence.

For example, the fruit fly can breed up to ten times in one hour.

The fruit fly, for example, can breed up to ten times in one hour.

Note how the addition of punctuation causes the reader to mentally pause and add emphasis to the phrase as they read.  

Example 2: Commas may be used to punctuate mild parenthetical expressions.

I was fired from my last job and consequently must look for a new one.

Or

I was fired from my last job and, consequently, must look for a new one.

In this example the punctuation affects the meaning of the sentence by changing the connotations of the word “consequently.” In the first sentence, the lack of punctuation sets up a distinct cause/effect relationship (because I lost my job I have to look for a new one), while in the second sentence, the cause/effect relationship is only peripheral, mentioned in passing. From this we can conclude that the use of punctuation with mild parenthetical expressions depends on the meaning that the writer wishes the sentence to convey.

In addition to our own website, this week we recommend The UT at Austin grammar practice website. This site includes lessons, activities, and tests and games about grammar, including activities for ESL students. Visit the UT at Austin website at http://www.utexas.edu/student/esl/computer/gram.html.

Test your understanding by correcting the following sentences. Remember that in some cases, the punctuation is optional depending on the meaning you wish to convey. Try punctuating it both ways to see how the sentence changes.

1. That parrot regardless of its pretty plumage is a nuisance and must be kept quiet!

2. Dinosaurs may have been wiped out due to an asteroid. However some people would argue against it.

3. This speech was perhaps a turning point in Gandhi’s career.

Answers

1. That parrot, regardless of its pretty plumage, is a nuisance and must be kept quiet!

2. Dinosaurs may have been wiped out due to an asteroid. However, some people would argue against it.

3. This speech was, perhaps, a turning point in Gandhi’s career. (This example could be considered correct with both versions of punctuation).

Grammatically Correct is a grammar tip of the week created by Academic Center Peer Writing Tutors at the University of Houston-Victoria in Victoria, Texas.

Comments about this newsletter should be directed to Summer Leibensperger, leibenspergers@uhv.edu.

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