Learning multiple languages (or dialects) is an incredible balancing feat for your brain, and even just studying a new language is a cognitive workout! We can think of the multilingual brain as turning the "volume" up on the language we're using at any given moment, and lowering the volume on the others—that's how we're able to use one at a time. For people who codeswitch or mix their languages in the same sentence or conversation, they need to have the volume up on multiple languages at once!

Here's what else we know about what's going on in the brains of multilinguals:

Our languages can have different cognitive "volumes."

How cognitively “loud” your languages are in the first place is related to things like the age at which you learned the language, how often you use it, and how proficient you are in the language.

It takes more mental energy to lower the volume on some languages than others.

You need more effort to lower the activation level of a language that you use more frequently, compared with inhibiting a variety that you have only learned recently.

When you're using a newer or weaker language, it takes more effort to switch back to your better language!

If you're an English speaker who has learned Spanish, that means that in order to speak in Spanish, your brain has to put in quite a bit of effort to really inhibit English. And then to switch back to English, your brain has to put in some effort to undo the effect of inhibiting English! These small delays—often no more than a few hundredths of a second—when switching between languages are known as “switch costs.”

Scientists study these tiny delays from stronger to weaker languages (and from weaker to stronger!) through experiments that require bilinguals to name pictures of objects aloud and by then measuring how long it takes them to start saying the name of the object.

The balance between languages is different for each bilingual and each combination of languages.

The exact volume of the languages and the "switch costs" between them depend on how much experience you have with each variety and how similar the languages are. For example, similar words, like cognates (such as English house and Swedish hus), tend to be named faster than words that are not related.

The volume of your languages can change over time.

Depending on how often we use and interact in a language, its volume can be turned up or down at different points in our life. If you used a language a lot growing up in your hometown but used it much less when you went away to university, its volume might have started quite high and been turned down. But that volume can be turned back up again later on, too!

The research speaks volumes 🔊

It's incredible how flexible our brains are—and how well-equipped they are to handle multiple languages. It takes time for a new language's "volume" to get as loud as our other languages, but the research shows that with time and lots of practice using the language, your brain will get the hang of it!