Most people in the world speak 2 (or more!) languages… which means there's a good chance you're among them! And if you're one of the many multilinguals studying a third or fourth language, you've probably learned firsthand that it feels different from learning a second language.

For your brain, learning a third language is very different from learning a second language, and there's good reason for that. Here's what's going on and what you can expect while learning a third language!

Bilinguals, unite!

There are many kinds of bilinguals and multilinguals (people who know more than 2 languages), and they have different experiences, proficiency levels, and ways of using their languages. What we all have in common, though, is that our brains have more to work with when it comes to language learning—we have (at least) two language systems at the ready!

Is it easier to learn a third language?

As a bilingual, you might have some advantages when learning a new language. 

Your brain is already a pro at managing multiple languages.
Knowing multiple languages means you've trained your brain to use neural resources in specific ways to balance and manage many languages. Bilinguals process language more efficiently than monolinguals do, and the more multilingual you are, the better your brain is at controlling attention and how and when it responds—the skills required for juggling multiple languages.

You’ve honed linguistic detective skills.
The more language learning experience you accumulate, the more tuned in you are to cues or patterns in the languages you’re exposed to

Whether your knowledge about these patterns is explicit (conscious knowledge you can describe) or implicit (knowledge acquired incidentally without conscious awareness), both kinds of knowledge can boost your pattern-deducing ability when you learn another language.

You don’t have to have advanced proficiency to reap the benefits.
It's normal for multilinguals to have different proficiencies and abilities in their languages, and even having limited proficiency in a second language can really boost your language learning efforts! In fact, sometimes your less-proficient language can have a greater influence on the third language than the more proficient one, typically when it’s similar to the third language. 

How your brain starts to learn a third language

Your brain could adopt different strategies to learning a third language: We might "copy and paste" one of our existing languages in its entirety and apply that at the beginning of learning a third language, or that copying-and-pasting could instead happen bit by bit, over time. The research says either might be possible! 

What we do know is that language similarity matters a lot.

You (and your brain!) are more likely to pull information and patterns from a language that's similar to a third language. For example, an Italian speaker who learned English and is now learning Spanish will likely rely heavily on Italian since Italian and Spanish share so many similarities.

What to expect for your third language

Your brain is trying to do you a favor by applying the rules of one language to your third language… but that doesn't mean your existing languages will always be a good match!

Many of the updates you'll need to make to your new third language system will be quick fixes, like learning (or correcting) new words. But learning new sounds and grammatical rules might take longer—especially if your brain pulled out a sound or structure from one of your existing languages that’s a mismatch. This is just part of the process, though: We can’t get it all right on the first try, and if that were the case, we’d all be hyperpolyglots!

As you learn a third language, you might also notice some changes in your existing languages. 

Languages can influence each other in both directions.

This is more likely to happen if your third language is similar to one of your existing languages, or if there's a notable difference in the relative strength of each of your languages. You might find that the new third language influences your vocabulary, grammar, and even accent in a language you already know! 

These changes to your existing languages can feel frustrating, but they’re reversible if you start using them more! They also sometimes play in our favor: When you learn a grammar structure in your third language that you hadn’t mastered in your second, it’s possible for that new knowledge to spill over.

Three’s not a crowd! 

Your bilingual brain is ready to take on a new language, and your previous language experience will give you a nice boost. You’ll encounter some bumps along the way, but the natural interaction between your languages is a cool display of how dynamic our brain is!