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Speaking of Which: Meaning, Grammar, and Proper Usage

In English, in everyday conversation with native speakers, you may come across certain phrases or expressions that you would rarely see in the written form. This written scarcity results from the abundance of expressions borne out of conversational usage, and “speaking of which” is such a phrase.

“Speaking of which” is used to introduce extra information to an existing conversation or a new idea to the last topic that someone has discussed or, at least, a topic they’ve very recently discussed. It is an expression using the pronoun “which” to refer back to a specific idea in conversational English.

Speaking of which, this article will take a closer look at why we use this phrase so often in everyday speech and why we tend to frown on it in the written form for more formal occasions. The article will also explore how to use it in conversation and accepted alternatives for the written form.

The Meaning of “Speaking of Which”

An individual speaker taking part in a conversation will often add the phrase “speaking of which.” We use it to add additional information to an existing topic, introduce a new idea that holds relevance to the existing or last topic in the conversation, or refer back to something that someone said in the recent past.

When one uses the phrase “speaking of which,” you are either extending a conversation you’re having with new information about the topic at hand, or you are adding to an existing discussion

by referring back to a topic that you just spoke about. 

It is important to understand that “speaking of which” is merely an expression that grew out of conversational English, and we only ever use it in everyday conversation. 

It is a verbal expression that many understand and accept in everyday speech, but you will not find it as readily in its written form, as we do not formally accept this construction in English.

The Dangling Participle 

There is a fairly simple reason why we don’t use “speaking of which” in a formal way and why you’ll hardly ever see it in its written form. 

As a non-native speaker and student of English as a second language, it is best to avoid “speaking of which” entirely when writing. However, if you are engaged in conversation, you can slip it into a sentence fairly easily. 

Most people do not use “speaking of which” in formal English because we can consider it a dangling participle.

In the English language, we call verbs and adjectives that end in -ing present participles. It is best to pay careful attention when you use present participles as they can confuse the meaning of a sentence when we misuse them.

Ordinarily, when you start a sentence with a present participle, it is often unclear which word in the sentence we are modifying with the participle in question. Consider the example below:

Sitting at the gate, a bee stung the boy. 

In the above example, the sentence can be confusing because the present participle or modifier does not function correctly. This is because the word that we are modifying with the present participle is unclear in this sentence. The meaning is confusing because it is not the bee sitting at the gate but the boy.

If you consider our article phrase, “speaking of which,” you can see that it could present the same issue. Starting a sentence with the present participle “speaking” may confuse the modifier and the word that we are modifying.

We call this type of incorrect use of the present participle the dangling participle, mostly because we leave the participle dangling at the beginning of a sentence, with the reader now unsure of the meaning of the sentence as a whole (source).

The Meaning of a Fixed Expression in English

The phrase “speaking of which” is what we call a fixed expression. A fixed expression means that we cannot rearrange the order of the words in the phrase and that it means a very specific thing. Fixed expressions are part of a subsection of English language studies, and they are many and varied.

We use a fixed expression as part of a sentence, which is where they differ from stand-alone proverbs. Still, idioms can also be fixed expressions as we often use these in everyday conversation and as additional parts to an ordinary sentence (source).

This means that you cannot alter the order of words in “speaking of which,” and you will always use it to add information onto a sentence and for no other reason at all.

Another fixed expression in English that follows much the same rules as our focal phrase is the phrase “with that being said.” It has a very similar meaning to “speaking of which” and shares a lot of other similarities as well. 

Second language English students that want to get a firm grip on and thorough understanding of proverbs, idioms, and other phenomena such as fixed expressions will do well to invest in helpful study aids. 

Using “Speaking of Which” in a Sentence

As we’ve stated previously, we will rarely see the phrase “speaking of which” when reading English; however, you can easily use it in everyday conversation and verbal exchanges or presentations.

The example sentences below might shed some more light on when and how to use this phrase in conversation appropriately:

I like watching football. Speaking of which, did you buy the tickets for next week’s game?

He doesn’t contribute to any group projects he’s assigned to. Speaking of which, do you know what the deadline for the geography project is?

I heard it’s going to be incredibly hot on Sunday. Speaking of which, remember to pack the sunscreen.

Julius Caesar was an important figure in Roman history. Speaking of which, I must remember to show you the documentary on him that I bought last month. 

Above, you can see we use the phrase “speaking of which” once we have completed a thought or idea in a sentence. However, the speaker adds additional information related to the previous topic in the next sentence and, therefore, begins that sentence with our focal phrase.

Sample Conversations

The following examples are conversations between two people:

Person A:    I do love watching football on Sundays; it’s a wonderful way to relax.
Person B:    Yes, I agree. Speaking of which, did you get tickets to next week’s live game?

Person A:    Harry doesn’t contribute to any of the group projects he’s assigned to. 
Person B:    I know! Speaking of which, do you know when the geography project is due?

Person A:    I am excited about the pool party on Sunday, and I heard it’s going to be really 
Person B:    It sure is! Speaking of which, remember to pack the sunscreen.

Person A:    We are currently studying Julius Caesar, an important figure in Roman history.
Person B:    I know all about him! Speaking of which, I must show you that documentary!

In each scenario from the examples above, Person B is completing the conversation with Person A and then using the phrase “speaking of which” to add new information, ideas, or concepts to the conversation that relates to the previous topic.

Does “Speaking of Which” Require a Comma

As with any fixed expression in the English language, there are certain hard-and-fast rules when it comes to punctuation. Generally, in English, a comma does not usually come after the word “which” except if one considers the part that follows as parenthetical content. 

Ordinarily, a comma also won’t precede the word “which” unless we are, once again, using parenthetical content.

However, when it comes to fixed expressions such as the phrase “speaking of which,” the rules differ slightly. There are eight rules for using the comma in American English, and one of these is to separate introductory elements from the rest of the sentence. 

If you start a sentence with an introductory phrase, setting the scene for the rest of the sentence instead of contributing to the sentence as a whole, you should separate it from the rest of the sentence by a comma.

If we use and abide by this rule, then we should always place a comma after the phrase “speaking of which” if we start our sentence with it, as we can consider this an introductory phrase.

Using a Semi-Colon or Em Dash

Additionally, the phrase “speaking of which” is always an introductory phrase. However, we can also use it in a way that relates closely to a previous sentence. 

In that case, we would use a semi-colon (;) or em dash (–) instead of a period before the phrase as the two sentences could stand on their own. The em dash tends to indicate an abrupt change in thought (source).

For example:

I do love watching football on Sundays as it is so relaxing; speaking of which, did you pick up the tickets for the match next week?

I am frustrated with Harry as he doesn’t contribute to any of the group projects that he’s assigned to — speaking of which, do you know when the geography one is due?

I understand that it’s going to be hot on Sunday; speaking of which, you must remember to pack the sunscreen!

Julius Caesar is such an interesting topic as he was such an important figure — speaking of which, I must show you that Roman history documentary I bought last month.

In conversational English, we often allow ourselves a short pause where we would place the comma in writing. 

Synonyms for “Speaking of Which”

Image by Julia M Cameron via Pexels

If you are having a conversation or giving an oral presentation, you can freely use the phrase “speaking of which.” However, if you were to do a written assignment or project, whether that be for personal or professional use, it is best to avoid this phrase.

In this case, if you still want to convey the same idea, there are some alternatives to use.

Many people may think that “which” and “that” are interchangeable in the English language and, therefore, you can use the phrase “speaking of that.” This is incorrect. The phrase “speaking of that” does not exist in the English language.

The best alternatives to the phrase “speaking of which” would be “if so,” “as for,” “relating to,” or “regarding,” as these expressions also indicate a relationship between what is coming and what you already spoke about.

For example:

James enjoys watching football on Sundays; as for Justin, he was only interested in whether or not James had picked up the tickets for the live game.

Patrick is frustrated because Harry doesn’t contribute to any group projects he’s assigned to. Relating to this, he asked one of their friends about the due date for the geography project.

I understand that it’s going to be hot on Sunday; if so, you must remember to pack sunscreen.

Regarding the fact that Julius Caesar was such an important figure in Roman history, I must remember to show you that documentary I got last month.

As you can see in the examples above, which phrase you choose to use will depend on the context of the sentence. Still, when speaking, you can freely use the phrase “speaking of which.”

Final Thoughts

The phrase “speaking of which” is a fixed expression in English that we rarely use in its written form; however, it is very common to hear and use it in everyday conversation. We use it to add extra information onto an existing sentence or introduce a new idea, concept, or thought related to the most recent topic of conversation.

We use this phrase most often when conversing with others, and we want to add our ideas into the mix. In this case, we always see this phrase in use at the start of a sentence.

Speaking of which, remember to put a comma after it when you do use it as an introductory phrase.