Sometimes we dream in languages other than our own, especially if in waking life we are multilingual. All this has a reason and a use
If we are lucky enough to remember what we have dreamed, we may be surprised to realize that we were having a conversation in our dream in a language other than our mother tongue, or in several languages that we know, even if we only have a basic level of knowledge. Why does this happen?
As author Sophie Hardach (‘Languages are good for us‘) explains for the BBC, sleep has “a more powerful role in language learning than previously thought“. Multilingual people often use several languages in their day-to-day lives, at home, academically or at work. This often carries over into the dream world, regardless of language. For example, deaf people have often explained that they dream in sign language.
This becomes more complex when the brain, while dreaming, mixes knowledge, day-to-day problems or worries. It is even sometimes able to create conversations in our dreams in languages we have only heard by hearsay or completely invented languages. Dreams of “language anxiety” are also common, when we dream that we do not understand a language or are not understood when we speak.
Dreams and language learning
“Dream scholars say that the exact mechanics and function of such dreams are quite difficult to establish, in part because dreams generally remain a rather mysterious phenomenon,” Hardach explains. To understand multilingual dreams, Hardach focused on understanding the role of languages in dreams and their impact on learning.
For example, when we use our native language, we also learn new words, even if we don't realize it. New terms or expressions that need to take hold in our minds, and this happens when we sleep. “It is during sleep that this integration of old and new knowledge occurs. During the day, our hippocampus, which specializes in absorbing information, integrates new words. At night, it passes the new information to other parts of the brain, where it can be stored and connected to other relevant information,” explains Hardach.
The same process occurs when we learn multiple languages. We store words that mean the same thing in different languages, and then use them in the correct linguistic context. This “process of integration and consolidation occurs during a phase known as deep sleep or slow-wave sleep,” says Hardach. This phase is not the same as dreaming, which tends to occur in the rapid eye movement (REM) phase.
In the light phase of sleep, we are more susceptible to language learning.
So what happens in the REM phase with languages? Many experts believe that the REM phase is when “things get sorted out and perhaps smooth out the rough edges,” explains Hardach. Matthieu Koroma, a researcher at the University of Liège in Belgium, specializes in sleep and cognition and explains that “the message is that you can learn words in other languages in your sleep, even new languages you've never heard before, but you do it in a very different way than when you're awake.”
In one study, participants were played different Japanese words associated with sounds. For example, “inu” associated with dog barking. This was done in both light sleep and REM sleep. It was shown that people remembered the words heard in the light phase of sleep, at the beginning of falling asleep, but had not learned anything in the REM phase, because their organism blocked external stimuli to focus on internal processes.
Sleep experts explain that, before we go crazy and listen to Japanese lessons while we sleep, so as not to disturb the hours of rest, the ideal is to learn languages while we are awake. Then, during sleep, our brain will be in charge of “classifying this information, consolidating some of our memories and trying to put them in new contexts“.