Why do we have multiple languages ​​in our dreams?

© Emmanuel Lafont

Leviathan Press:

I remembered a dream I had before. In the dream, I was talking to someone in a very strange German language. The other person was confused and said in Chinese: You are not speaking German! After waking up from the dream, I was also very curious about why there were pronunciations other than my native language (even completely fictional languages) in my dreams. Today's article may be able to answer this question for many people.

In addition to speaking foreign languages ​​in dreams, there is another particularly interesting thing about our brains at night: every time we sleep, our brains will undergo a "brainwashing" process - yes, literally brainwashing. Your neurons will then become quiet. After a few seconds, blood will flow out of your brain. Then, a clear liquid called cerebrospinal fluid will flow in, rhythmically "washing" your brain.

© Laura Lewis

Just as I was beginning to write this article, I had a very fitting dream. In the dream, I was hosting a party in a hotel suite, and the room was filled with guests from the United States, Pakistan, and other countries. Most of them spoke English; one or two spoke German, my native language. Suddenly, I realized that my son was missing, and I began to panic. When I finally found him, I breathed a sigh of relief: "Ach, da bist du ja!" (German: So there you are!) - and gave him a hug.

If you speak more than one language, you may have similar experiences of mixing up languages ​​in your dreams.

My dreams often involve English, the language I now speak in my daily life in London, and German, the language of my childhood. How exactly are our brains able to program these multilingual dreams, and how do they affect our real-life language skills?

Decoding the language of dreams

Many multilingual speakers use these different languages ​​in their dreams, even beginners who have just learned a foreign language[1]. This conclusion does not seem surprising at first glance, after all, it makes sense that the languages ​​we use in our daily lives would be carried over into our dreams. A study of deaf and hard of hearing people showed that they communicated in their dreams in the same way as when they were awake: using sign language [2].

On closer inspection, however, multilingual dreams reveal a more complex and nuanced picture. For one thing, rather than randomly replaying snippets of waking language, our brains are more likely to be jumbling together a variety of everyday anxieties, memories, and problems. It may even create new, unknown fantasy languages[3] or languages ​​that the dreamer has heard but not understood in waking life (in my dreams, I sometimes speak endlessly in Japanese, a language I once learned but eventually gave up on in real life).

© Emmanuel Lafont

Most people will classify the use of language in dreams in some form, based on people, places, or different stages of life. For example, the people in the dream may speak the language they speak in real life, and when the dream location takes place in the dreamer's childhood home, the language of the people will change to the language used in the dreamer's childhood - but such views still need to be verified with caution, because there are only a few studies on multilingual dreams.

Furthermore, dream language seems to be superimposed on culture and identity, as in one case of a Thai-American woman who dreamt about buying a dress for her deceased sister and argued with her niece in both Thai and English.[4]

In addition, there are "linguistic anxiety dreams". The protagonists in these dreams are usually worried about not being able to understand a foreign language. The scenes can appear when catching a bus, catching a plane, or looking for words in a dream dictionary, etc.

In one study from Poland, a participant reported dreaming about an English word she did not understand—“haphazard”—and looking it up in a dictionary upon waking. A participant from Croatia dreamed about trying to communicate with a stranger in Italian, German, and English but failing, only to laugh when she discovered that the stranger also spoke Polish.[5]

Sleep researchers say the exact mechanisms and functions of such dreams are difficult to explain, in part because dreams remain a largely mysterious phenomenon. But we now have a better understanding of how and why our brains process language during sleep, and even how we learn new words. Understanding this could at least shed some light on the puzzle of multilingual dreams.

A brain working overtime in dreams

To understand the connection between sleep and language, we need to start with a language: your own. You may think you mastered it a long time ago, but in fact, our native language is constantly being updated. Even adults continue to learn their native language at a rate of one new word every two days[6].

“Obviously when we’re children we have a lot of new words to learn, especially in the first ten years of life, but we’re doing it all the time without really paying attention,” says Gareth Gaskell, professor of psychology and head of the Sleep, Language and Memory Laboratory at the University of York.

Whenever we learn a new word, we are actually constantly building blocks around it, adding new knowledge until it is solid and reliable. Gaskell gives the example of "breakfast": although this is a simple word that almost everyone can use with ease, when another word with a similar pronunciation appears, the existing word becomes uncertain.

© Emmanuel Lafont

“At some point in the last five years you probably learned the word ‘Brexit’ and that was a competitor to ‘Breakfast’,” he said.

Confusion also ensued as the new word "Brexit" and the existing word "Breakfast" appeared in people's minds at the same time. More and more news broadcasters and politicians used phrases such as "Brexit means breakfast" and "ploughing ahead with a hard breakfast".

To use these new words properly and distinguish them from similar-sounding words, we need to connect them to our existing knowledge . “And the way to do that is through sleep,” Gaskell added.

This fusion of old and new knowledge happens during sleep. During the day, our hippocampus absorbs information quickly, soaking up new words like a sponge. At night, it transfers this newly acquired information to other areas of the brain, where it can be stored and linked to other relevant information.[7] This form of storage helps us choose the right word in any situation and suppress conflicting words.

Tag "mental dictionary"

This process is the same whether we are learning a first or second language, according to Gaskell. In the case of multilingual learners, foreign language vocabulary is stored in the same large mental database and is selected or suppressed by the brain in the same way.

“You can imagine that there are some kind of labels in your memory,” Gaskell said. “So when your mental dictionary has German and English words, each language you know is labeled so that when you have a conversation you focus on the words you want and suppress the other half. ”

Was this what I was doing in my dream, in a hotel filled with people speaking both English and German—by sorting and categorizing the languages ​​in my head and labeling them with meaning?

This would be a wonderful explanation, but unfortunately, the process of consolidation occurs during what we call deep sleep, or slow-wave sleep. This stage is characterized by slow brain waves and higher frequency spindles [8]. Complex dreams, such as my hotel dream, tend to occur in another stage, rapid eye movement (REM).

© Arizona RETINA Project

“Some people think REM sleep plays a role in this whole consolidation phase, sorting things out or smoothing out rough edges,” Gaskell says. According to my dream, which I had snuck away from a party to attend a BBC panel online, he says: “It’s a classic scenario where some of your recent memories are entangled with more ancient knowledge. It fits in with the theory that dreams help consolidate memories, although it’s just a hypothesis at the moment.”

You can learn words from other languages ​​in your dreams, but it will be very different from the way you learn them when you are awake.

We know that in addition to processing information from the day, the brain is also able to learn new words while it sleeps.

Marc Züst, a research group leader at the University Hospital for Geriatric Psychiatry and Psychotherapy in Bern, Switzerland, specializes in the neuroscience of aging, sleep, and memory. He and his research team invented a set of fake words, such as "tofer", and then paired it with a German word, such as "Baum" (tree), and changed the meaning of these words between different subjects to ensure that the matching was random and had nothing to do with the underlying sound association. Then they repeatedly played recordings of the two related words after the subjects fell asleep.

The next morning, the researchers asked them whether the tofer would fit into a shoebox. This roundabout way of asking questions is to follow a known rule: any information acquired during deep sleep is usually not consciously and explicitly used in the waking state.

"They weren't able to consciously recreate that information and say something like 'tofer must mean tree,'" Zuster said of the subjects. "They were judging the size of this object in a more intuitive way." About 60% of the subjects correctly answered the question of whether "tofer" could fit in the shoebox.

Crucially, both words (“tofer” and its German counterpart) had to be played during a phase of slow-wave sleep, or more precisely, at the peak of slow-wave sleep. If the researchers missed the peak, the word-meaning matching lost its effect.

Matthieu Koroma, a postdoctoral fellow studying sleep and cognition at the University of Liège in Belgium, has co-authored a series of studies that shed more light on exactly how and when we interact with language in our dreams.

"In general, you can learn words from different languages, even languages ​​you've never heard of, while you're asleep, but the process is very different from how you learn when you're awake," he said.

First, he and his team discovered that we can distinguish true and false language even in our dreams. After falling asleep, the subjects played different voice clips in both ears at the same time: one ear heard "real" speech containing information from their native language, while the other ear played a voice clip composed of fake words. The researchers recorded the subjects' brain activity during this period through electroencephalography (EEG).

Electroencephalogram results showed[9] that the brains of sleeping subjects tended to focus more on meaningful speech fragments rather than fake ones. However, during the rapid eye movement period when dreams are frequent, the subjects tended to shut down or inhibit external speech input. Koroma speculated that this might be because the brain is more focused on internal information processing during the rapid eye movement period: "When we are immersed in dreams, anything that may disturb the dream will be rejected."

© Emmanuel Lafont

In another study by the same team[10], the researchers played Japanese words and corresponding suggestive sounds while the subjects were falling asleep. For example, the word "いぬ" (dog) was played with the sound of a dog barking; the word "かね" (bell) was played with the sound of a bell. Different words were played during two different sleep periods: light sleep and rapid eye movement (REM) sleep, when dreams are frequent. Similarly, the researchers recorded the subjects' brain activity using electroencephalograms.

In the awake state, the subjects were able to associate the words heard during light sleep with the relevant pictures (for example, the word "いぬ" and the picture of a dog), and the accuracy rate was higher than that of blind selection. However, the accuracy rate of matching the words played during REM was almost the same as random selection.

" Whenever we looked at REM sleep, the period when dreaming is most active, we couldn't find conclusive evidence for learning, " Koroma said. This doesn't mean we can't learn during this period, but it does mean more research is needed to confirm whether this theory is feasible.

Enhance daytime learning ability

Does this mean that we can effortlessly learn Japanese while snoring away, as long as we play Japanese learning courses throughout the night to ensure that we can hear them during the important sleep stages?

Not necessarily. It may actually backfire and disrupt your rest, argues Koroma.[11] He also points out that in his experiments, subjects learned words much faster while awake than while asleep: “You’re much more efficient when you’re awake.” They were also able to use the words more confidently because they were learning them consciously.

"Wakefulness is better for learning, while sleep is more focused on reviewing rather than acquiring new language," Koroma said. "It's an interactive process and it's complementary, meaning that when we finish the daytime learning phase, we go to sleep at night to organize that information and consolidate some of it into our memory, storing it in another place."

© weblio news

So, are there other ways to use sleep to learn languages?

“The best approach might be to do language learning before bed and then play some of the words you’ve heard while you sleep,” Koroma said. “ The good thing about this approach is that as long as you play it at a low enough volume, your learning ability will improve [12]. But if the volume is too loud, it will reduce your learning ability. So you have to be moderate.”

Zuster of the University of Bern recommends learning new words during the day, but at night "focus on getting enough sleep, and your brain will figure out what to do next."

Problem Solving in Sleep

When it comes to the potential role that multilingual speakers play in sleep learning, the researchers become cautious.

"It's very, very hard to figure out how multilingual dreaming happens in this process," Zuster said.

Part of the reason is that many of the cognitive purposes of dreams are still unknown. One theory is that they are more like "the residue left over from the active brain's sweeping of memory traces," according to Zuster. This doesn't mean that dreams have nothing to do with the language learning process - just that they may be a consequence, not the main event.

“It’s entirely possible that in multilingual dreams, our brains are trying to bridge the two languages,” Zuster says, but the messy, separate nature of dreams and natural languages ​​makes it hard to say for sure.

Koroma points out that REM sleep is associated with problem-solving and emotion regulation processes, so dreams may allow us to try out new words and sentences in different contexts, or explore the emotions that come with speaking these words.

Danuta Gabryś-Barker, a professor of psycholinguistics at the University of Silesia in Poland, came to similar conclusions in a study analyzing dreams among multilingual people, suggesting that such dreams can express “fears and desires” related to learning a foreign language, including the desire to become a native speaker.

This idea is consistent with the hypothesis mentioned above that playing with words in dreams may help improve creative verbal expression and problem-solving skills, and both mention the role of dreams in emotional processing.[13][14] However, as Koroma and others emphasize, this is only a possibility, not a solid fact.

© Harvard Gazette/Harvard University

This adds a layer of mystery to my multilingual dreams, at least in terms of their actual function. But it’s amazing to see the hidden effort that goes into even a single word through this late-night performance of my brain. Not only that, I learned a new word while writing this article, though not in my dreams.

The French word is hypnopédie. I learned it from Belgian researcher Koroma, who used it in an article. It's been a few nights since I learned about it. I've often wondered what labels and associations my brain would give to this word in the dead of night? Perhaps French, Belgian, sleep, and deadlines? Either way, it sounds like an interesting start to a dream.

References:

[1]www.tandfonline.com/doi/abs/10.1080/14790718.2012.755187

[2]psycnet.apa.org/record/2007-04668-004

[3]link.springer.com/chapter/10.1007/978-3-319-14334-7_1

[4]digitalcommons.ciis.edu/cgi/viewcontent.cgi?article=1495&context=ijts-transpersonalstudies

[5]hrcak.srce.hr/en/file/294766

[6]www.frontiersin.org/articles/10.3389/fpsyg.2016.01116/full

[7]www.jneurosci.org/content/30/43/14356.long

[8]www.jneurosci.org/content/31/49/17821

[9]www.cell.com/current-biology/pdfExtended/S0960-9822(20)30561-3

[10]www.frontiersin.org/articles/10.3389/fnins.2022.801666/full

[11]www.nature.com/articles/s41539-019-0044-2

[12]academic.oup.com/cercor/article/25/11/4169/2366428?login=false

[13]www.cell.com/current-biology/fulltext/S0960-9822(10)00352-0

[14]www.frontiersin.org/articles/10.3389/fpsyg.2019.00459/full

By Sophie Hardach

Translated by Ishmael

Proofreading/Rabbit's Light Footsteps

Original article/www.bbc.com/future/article/20230213-how-people-dream-in-foreign-languages

This article is based on the Creative Commons License (BY-NC) and is published by Ishmael on Leviathan

The article only reflects the author's views and does not necessarily represent the position of Leviathan