Grammar Girl Quick and Dirty Tips for Better Writing

How Using Pliers Improves Your Language. Weird Possessives. Ducky File.

Episode Notes

An amazing study shows that tool use and language are connected in the brain and shows how using one can make you better at the other, and vice versa. Plus we look at some tricky possessives. Can you say "a friend of mine's car"?


The tools and language segment is by Claudio Brozzoli a researcher at INSERM Lyon Neuroscience Research Center, and the Impact team at the Karolinska Institute, and Simon Thibault, a Postdoctoral Researcher at Lyon Neuroscience Research Center. It originally appeared on The Conversation and appears here through a Creative Commons license. Read the original (without my interjections).

Subscribe to the newsletter for regular updates.

Watch my LinkedIn Learning writing course.

Peeve Wars card game

Grammar Girl books

| HOST: Mignon Fogarty

| VOICEMAIL: 833-214-GIRL (833-214-4475)

| Grammar Girl is part of the Quick and Dirty Tips podcast network.

| Theme music by Catherine Rannus at

| Grammar Girl Social Media Links:

Episode Transcription

Grammar Girl here. I’m Mignon Fogarty, and you can think of me as your friendly guide to the English language. We talk about writing, history, rules, and other cool stuff.

Today, I'm going to start with a study about language that blew my mind, and we'll end by talking about tricky possessives.

This first piece is by Claudio Brozzoli and Simon Thibault from the Lyon Neuroscience Research Center writing about their research.

Language has traditionally been considered a complex skill that mobilises brain networks specifically dedicated to linguistic processing. But in recent years, neuroscience research has returned to this idea and offered new insights.

Notably, studies have suggested that areas of the brain which control certain language functions, such as processing the meaning of words, are also involved in the control of fine motor skills. 

Syntax, the ability to correctly structure words into a sentence, is one of the most important features of language. While evidence had yet to link syntax skills specifically with motor control in the brain, research published in 2019 revealed a correlation between having good syntactic ability and being skilled at using tools. 

With this in mind, our international research team was interested to know whether the use of tools engages parts of the brain similar to those mobilised when we’re thinking about the construction of sentences.

We invited participants (244 across a series of experiments) to perform tests consisting of motor training and syntax exercises in French. Our new findings, published in the journal Science, show that these two skills do engage the same region of the brain. We also found motor training with a tool improves our ability to understand the syntax of complex sentences, and vice versa. 

For the motor training, we asked participants to use mechanical pliers to insert small pegs into different holes. In the syntax exercise, participants were shown sentences such as “The scientist who admires the poet writes an article” or similar sentences with more complex syntax like “The scientist whom the poet admires writes an article.” They then had to judge statements such as “The poet admires the scientist” as being true or false.

For the first part of our analysis, we used brain imaging techniques (functional magnetic resonance imaging, or fMRI) to identify the brain networks activated during each task.

We observed that the motor training and the syntactic exercises activated common areas of the brain in a region called the basal ganglia. The two tasks activated these common parts of the brain in similar ways (for example, we observed similar distribution of the activations). 

We wanted to know more

Once we had ascertained that these two skills use the same brain resources, we wondered, is it possible to train in one to improve the other? Would motor training with the mechanical pliers improve comprehension of complex sentences?

So in the second part of our study, we invited a new sample of participants to complete a syntactic comprehension task before and after a 30-minute motor training with the pliers.

In the syntax task, we found that after motor training, participants performed better with sentences considered more difficult compared to before motor training.

To be confident this improvement wasn’t an effect of having completed the syntax activity earlier, we compared these results with three control groups – one that did not receive any motor training between the syntax activities (they were shown a wildlife video) and two groups that were given motor training tasks to complete with their bare hands. None of these groups showed a significant improvement in the language task. 

We also had a group of participants complete the pliers exercise before and after a modified version the language exercise, to ascertain whether the reverse was true. We found practising complex syntactic skills improved motor performance with the tool, though training with simpler syntactic structures did not.

Future applications

Paleoneurobiology, the study of the brain’s evolution, has indicated that brain areas related to language increased in our ancestors during times of technological boom, when the use of tools became more widespread.

Taken together with modern neuroscience research, this link between language and tool use in the brain is not new. But as we continue to build our understanding in this space, we pave the way to harness this association for good.

We are now considering how we could apply our research findings clinically. For example, it might be possible to support the development of language skills in some patients with relatively well-preserved motor skills, such as young people with developmental language disorders.

Again that piece was by Claudio Brozzoli a researcher at INSERM Lyon Neuroscience Research Center, and the Impact team at the Karolinska Institute, and Simon Thibault, a Postdoctoral Researcher at Lyon Neuroscience Research Center. It originally appeared on The Conversation and appears here through a Creative Commons license. You can find a link to read the original in the show notes, and I hope to hear more about their research in the future because it's just fascinating.


Next, we're going to talk about something people regularly ask about: weird possessives.

"Hi. Mignon. I had a quick question for you. My son called me tonight because he saw something on somebody's Instagram story that he was sure was not correct grammar, but his fiancée was sure it was just fine, and I wasn't 100% sure about what the right answer was. What the post said was the … they referred to 'a friend of mine's cousin,' and he wasn't sure if that was correct,  if you put 'mine' and the possessive and the extra possessive. And he said wouldn't it be better to say 'my friend's cousin,' and I agree 'my friend's cousin' is much simpler and better, but does that mean 'a friend of mine's cousin' is wrong. Let me know what you think. Thanks. Bye."

Thanks so much for the question.

Phrasal Possessives

"Mine's" is definitely not a grammatically correct word. "Mine" is already possessive, so adding an apostrophe-s to make it possessive doesn't make sense, but something else is actually going on in this sentence fragment: "A friend of mine's cousin." "A friend of mine's" is what's called a phrasal possessive, and it just seems especially weird when the phrase ends with a word that is already possessive like "mine."

A less weird phrasal possessive happens in a sentence like "The United Kingdom's crown jewels are on display." "United Kingdom" is two-words, and we make it possessive by putting the apostrophe-s on the last word.

Something like "The guy I carpool with's car has a flat tire" is much more unwieldy, but is also a phrasal possessive. We're making the phrase "the guy I carpool with" possessive. It's his car. Alone, we'd say the word "with's" (with-apostrophe-s) isn't right, but we're not making just that word possessive, we're making the whole phrase that describes the man possessive.

And then again, the pinnacle of weirdness, the pièce de résistance, is when the last word in the phrase is already possessive, like "A friend of mine's cousin." I mean yuck! It's cringey!

But that's not what you asked me. You asked me if it's wrong. And I have to say no. It's not grammatically incorrect. But it's definitely something you should try to avoid. I mean, if it stands out so much your family is debating whether it's correct or not, that's a big clue that you can do better. And style guide writers don't like the phrasal possessive. For example, Garner's Modern English Usage says, "avoid phrasal possessives when possible." (1)

Double Possessive

But let's back up a bit because there's also something a little simpler called a double possessive. We had a question a few years ago from a listener named Cathy who asked “Which is correct—‘I am a friend of Fred’ or ‘I am a friend of Fred’s’?” And she pointed out that it would sound normal to say, “He’s a friend of mine,” and “mine” is the possessive, so she wondered if that means "Fred" should be possessive.

Cathy’s right, that you usually use only one possessive at a time. Again, although double possessives are grammatically correct, many purists believe that double possessives should be relegated to informal and semiformal writing, if you use them at all. Nevertheless, double possessives have appeared in good writing for centuries, and most people will use them at least every once in a while (2).

How to Create Possessives

One way to use possessives is to indicate who owns what. If Squiggly owns a car, you say, “This is Squiggly’s car.” You use an apostrophe plus an S on the end of “Squiggly.” You can also form a possessive by using the word “of,” such as “The crown jewels of the United Kingdom.” (Of course, you could also say, “the United Kingdom’s crown jewels” using the phrasal possessive that we talked about before.) These examples are just normal possessives. There’s nothing double about them. The confusion arises when you use both ways of making possessives at the same time, as in “a friend _of_ _Fred’s_.” Here you have the word "of" plus an apostrophe-s. Although such a double possessive is allowed, most style guides say it's better to rewrite it to something like “Fred’s friend.” Instead of saying "He's a friend of Fred's," why not just say, “He’s Fred’s friend”?

Incorrect Possessives

Nevertheless, to help us learn what’s right, let’s look at some possessives and double possessives that native speakers wouldn’t use. It definitely sounds odd to say, “a car of Squiggly.” On the other hand, you could say, “a car of Squiggly’s,” assuming he has lots of cars and you’re pointing out one of them. However, “a car of Squiggly’s” doesn’t sound as natural to me as “one of Squiggly’s cars.”

On the other hand, it’s perfectly normal to say, “the crown jewels of the United Kingdom” or “the United Kingdom’s crown jewels,” but it turns out that it’s ungrammatical to say, “the crown jewels of the United Kingdom’s.” In this case, there's a clear-cut rule: When you’re talking about inanimate objects—objects that aren’t alive, such as “the United Kingdom”—you can’t use a double possessive (3). According to The New Fowler’s Modern English Usage, for a double possessive to be legit, the object of the preposition “of” has to be “definite and human.” In other words, it’s fine to say, “a friend of my uncle’s” but not “a friend of the museum’s.” You have to say, “a friend of the museum.” However, according to this rule, it would be OK to say, “He’s a friend of a friend’s,” but we’ve all heard the common expression “He's a friend of a friend.” I guess double possessives don’t always work or at least aren't always necessary. So that should make some sticklers happy.

Avoiding Double Possessives

We could clear this all up by telling  you that you should just always avoid double possessives. Maybe that would make life easier. Instead of “a friend of my uncle’s” or “a car of Squiggly’s,” maybe we should always say, “my uncle’s friend” or “Squiggly’s car.” For the most part, you won't go wrong if you follow that advice.

Useful Double Possessives

But there are some cases where a double possessive actually does help clarify your meaning.

This example comes from all the way back in 1768 when Jospeh Priestly, a famous language writer of the time, highlighted a particularly tricky sentence about pictures. (2) If you attempt to avoid the double possessive and say something like “This is Marie’s portrait,” you end up with an ambiguous sentence that could mean you are looking at a portrait of Marie or a portrait that is owned by Marie. You can fix the problem by substituting one of two sentences depending on what you mean. If you mean Marie owns the portrait, then the double possessive makes it clear: “This is a portrait of Marie’s.” On the other hand, if it is a lovely rendering of Marie, “This is a portrait of Marie” will serve you well.

Another time when you might need to use a double possessive is if you want to use a possessive pronoun, such as “theirs,” “hers,” or “mine,” as Cathy noted in her initial question. In fact, it’s impossible to avoid using a double possessive in cases such as “She is a relative of his.” If you don’t like double possessives, you could reword such sentences by saying, “She is his relative,” “She is one of his relatives,” or, simply, “They are related.”

Double possessives might also be necessary if you’re using a “that,” “those,” “this,” or “these” in your possessive (4). For example, “the hat of Aardvark’s” sounds a bit odd to me, whereas “that hat of Aardvark’s” sounds a lot more natural. And maybe it's not surprising that "that hat of Aardvark's" also sounds like something of an informal statement.

In Summary

That question of Cathy’s was pretty tricky. Or, it might be better to say, “Cathy’s question was pretty tricky.” Instead of "I am a friend of Fred's," the better choices for her are “I am a friend of Fred,” or “I am Fred’s friend,” or even “Fred is my friend.”

The double possessive and the phrasal possessive are grammatically correct and do have legitimate uses, but you should probably avoid them in formal writing unless doing so sounds unnatural or causes confusion.

The double possessive part of that segment was written by Bonnie Mills, who's been a copy editor since 1996, and I wrote the part about phrasal possessives.


Finally, I have a familect story from Jane.

Hi, Mignon. I'm Jane. And I have a family story from Australia. I've got six children. And when we went out for walks, when they were little and they were following behind me, they looks like little ducklings home. Instead of saying 'single file,' when we had to pass people on the path, I'd say 'ducky file' and that all line up behind even as adults. Now if we're walking together, I say ducky file, and they all automatically fall back on the very proud mother duck. Thanks mean you love your show?

Thanks, Jane. I love that story. It's so cute.

Next, someone who found me on TikTok reminded me that I should actually tell people I'm on TikTok. Good point! I've been making a lot of videos there lately and on Instagram too. I'm therealgrammargirl on TikTok and thegrammargirl on Instagram. That's what happens when you're late to making your account! But come say hello.

Grammar Girl is a Quick and Dirty Tips podcast. Thanks to my editor Adam Cecil and my audio engineer Nathan Semes, who usually cans his own salsa, but will be adding San Marzano marinara to the list this year. Our ad operations specialist is Morgan Christianson, and our digital operations specialist is Holly Hutchings. And a fond farewell to our intern Brendan Picha. You've been great, Brendan, and I hope you have a long future filled with hiking and axe throwing and wherever your professional path takes you.

I’m Mignon Fogarty, better known as Grammar Girl. That's all. Thanks for listening.

Additional information not in the audio:


1. Garner, B. Garner’s Modern English Usage, fourth edition. Oxford: Oxford University Press. 2017, p. 714.

2. Gilman, E. W., ed. Merriam-Webster's Dictionary of English Usage. Springfield: Merriam-Webster, Inc. 1994. p. 364.

3. Burchfield, R. W., ed. The New Fowler’s Modern English Usage, third edition. New York: Oxford, 1996, p. 227.

4. Garner, B. Garner’s Modern English Usage, fourth edition. Oxford: Oxford University Press. 2017, p. 713.