How Well Adults Can Learn a Second Language Revealed


Learning a second language is beneficial for many reasons, whether personal or professional. As children, people acquire language naturally from their environment, absorbing sounds and associating them to concepts with ease. But what about adults? How well can they learn a second language?

Adults can acquire almost perfect second language fluency, but it is harder and less likely than for those under the age of 18. The process is more cognitively complex and time-consuming due to differences in lifestyle between adults and children. However, this does not make it impossible.

Children may acquire language more naturally than adults, but that does not mean they alone can reach high levels of fluency in foreign languages. Adults may become just as fluent as a native speaker if they are willing to put in the work. Read on to learn more about the ins and outs of adult language learning.

How Well Adults Can Learn a Second Language Revealed

I recommend Steve Kaufmann’s site LingQ for anyone that likes reading and subtitles for songs and videos in their target language. Sign up for LingQ here for free.

A second language is defined as any language you learn after your native-tongue or the one you grew up speaking. The way we learn our first language lends huge insight into how adults do the same with a second language, something that has long been hailed as unfeasible by adult learners. But why is it so difficult?

We know that it is almost inconceivable to replicate the exact process we all live as children learning our first language. After all, while children absorb language, adults piece together aspects of it. Research has even shown that a child’s brain is wired to learn an unlimited amount of languages, while adults are generally more limited.

According to linguistic experts, the ideal window for learning a language is between the ages of 2 and 18 years old. Outside this threshold, language becomes more complicated to learn and harder to master. Experts suggest that this occurs for many reasons, including:

  • Lifestyle
  • Social conditioning
  • Lack of immersion

To understand how well adults learn a second language and how difficult it truly can be, we must first understand the science behind the process. What happens in and to the brain? What are the benefits of learning a second language?

The Science Behind Learning a Language

Every experience we have triggers a change in our brain, and that includes learning a language. Being multilingual not only affects how our brain works but also morphs its physical anatomy. According to a study by Stein et al. (2012), second language acquisition can result in the following:

  • An increase in the amount of gray matter in the brain, especially in the frontal lobes. Gray matter is directly associated with intelligence, memory, attention, and language.
  • Structural changes to the prefrontal and temporal lobes.

Another study published in the Journal of NeuroImage suggests that:

  • Second language acquisition can increase neuroplasticity in the brain. Neuroplasticity is associated with the brain’s ability to create new neural connections in response to the experiences we live.
  • Learning a new language increases white matter in the brain. The white matter in our brain directly controls how fast we process and recall information.

Taking all this into consideration, we can conclude that learning a second language does not only facilitate communication, but it makes you smarter and increases overall verbal fluency skills.

Cognitive Flexibility

Some studies even suggest that cognitive flexibility, which declines as we age, can be curbed by learning a second language. Multilingual brains are under more strain than monolingual brains: they are forced to switch between languages or suppress whichever is not being used. This builds executive controls in the brain, improving:

  • Multi-tasking skills
  • Task-switching ability
  • Control
  • Focus

Bolstering these skills and strengthening our brain can offset cognitive decline due to age and delay the onset of diseases such as Alzheimer’s and dementia. Overall, learning a second language comes with a plethora of benefits, especially for adults. So what’s the best and easiest way to do it well?

Learning a Language: Children Vs. Adults

Learning a second language can be an easy or difficult task depending on your age (I’ve addressed the best age to learn a second language in another article, too). Some aspects of being an adult are advantageous to language acquisition, including:

  • Increased cognitive levels
  • Refined critical thinking
  • Self-analysis

However, many other consequential and environmental factors of age can greatly hinder how well you learn a second language and how difficult it can be. Studies have shown that the most successful language learning occurs in immersive, low-pressure environments.

Learners are encouraged to associate sounds and words to concepts, making natural connections in their brains and not simply translating to and from their native tongue. Students are not forced to produce speech or writing before they are ready and learn a natural progression of vocabulary and grammar directly influenced by life experiences.

This above ideal learning style is seen in children. A stark contrast presents itself: adults learn a language, while children acquire it. The difference lies in how the language is assimilated into the brain and the level of mastery that one can achieve. So what exactly is the difference?

Acquisition Vs. Learning 

There are generally two verbs associated with the process of assimilating a second language: acquisition and learning. Though they may seem similar, there are distinct subtitles between the two verbs. They represent different ways of getting to the same end goal, speaking a second language.

Language acquisition comes naturally to children. Children do not begin speaking at birth, but over time are exposed to the sounds and ideas that make up a language. They are not forced to sit down and memorize words or grammar. Instead, children naturally link specific sounds and words to what they represent.

Consider the differences between children and adults.

  • Learning for children is stress-free. There are no tests or quizzes to worry about or any vocabulary to translate and memorize. They are not forced to speak before they feel ready, reducing anxiety and facilitating knowledge absorption. The language is acquired slowly and through immersive methods and meaningful interactions.
  • Adults learn a language differently. Instead of creating natural connections between words and what they represent, adults are forced to translate back and forth between their mother tongue and their target language. Many studies show that this form of “translation learning” results in poor knowledge retention.

Often, adults do not fully learn or understand the construction of the language but are only able to memorize its content. This also hinders mastery and fluency. The question now begs to be asked: is it possible for adults to acquire a language the same way children do? Is it possible to achieve an equivalent level of mastery?

How Do Adults Learn a Second Language?

Often how we learn a language can be directly linked to our age. Experts suggest that the ideal window for language learning is between the ages of 2 and 11 or 18, depending on the study. It can be shocking news to some that a fully capable adult with life experiences and skills can fall behind a young child.

However shocking it may be, science shows that this is reality. On average, adults require more time and effort to achieve the same skill level as children. The playing field is not equal, to say the least. However, when we take a closer look, things begin to make a lot more sense.  

So how exactly do adults learn a language, and how well do they do it? It is clear that younger populations learn languages with much more ease and accuracy than adults, but what is the reason behind this? Can we link this phenomenon back to science – how our body changes as we age? Or lifestyle?

Science Vs. Lifestyle

Scientists have long believed that neuroplasticity declines over time, making it anatomically harder for adults to learn new skills. Modern brain imaging studies now undermine this theory, showing that practice-induced task learning – like learning a second language – changes the structure of the brain, just like in children (Source: Dialogues in Clinical Neuroscience).

A recent study by MIT has further debunked this theory, showing that plasticity is not to blame for increased learning difficulties, but rather the lifestyle habits of adults. Before the age of 18, circumstances generally lend themselves to the ease of learning a language. These include: 

MotivationsAs an adult, our motivations to learn a language may stem from non-essential desires, like travel. For children, learning a language is not necessarily the goal, but simply a by-product of it: to make a friend on the playground, one must be able to speak their language.
Language ExposureAfter the age of 18, adults undergo drastic lifestyle changes. Often this is the age when they enter the workforce or go to college, meaning they have much less time to spend on learning a second language. Children are constantly exposed to their target language, and the process happens slowly over many years.
Self-analysisChildren generally have lower expectations for themselves, as they have not yet learned otherwise. This means that learning does not provoke anxiety but rather is an experience. Low-pressure learning is conducive to better knowledge retention and mastery.
Structure VS. contentAs children learn, they pick up grammar and structures in a natural order and are not fed grammar too soon when they are not yet prepared. Adults learning in a classroom often may be exposed to structures before they are ready and are forced to simply memorize the content without fully understanding it.
SpeechChildren have years of exposure to their target language before they even try to produce speech. Only when they are ready do they take the opportunity to practice what they learn. Adults, contrastingly, do not have the same luxury, especially when it comes to classroom learning.

Adults are scientifically just as capable of reaching true fluency and mastery of language as children are. However, they are forced to work harder and more creatively to achieve the same results.

It is reassuring for aspiring adult polyglots to know that lifestyle, and not the physical anatomy of our brains, is the reason behind increased learning difficulty. Though this knowledge may not facilitate the process of learning, it reiterates the fact that mastery and fluency are realistic and attainable goals for both adults and children.

Adults Cannot Learn Languages Well: Debunked 

So now we know that adults can be successful in learning a second language, but just how successful can they be? Can an adult learner reach the same fluency level as a native speaker or child?

In the same study by MIT on adult language learners, results further the theory that language mastery is still possible, even after the age of 18. Though it is clear that the advantages lie with younger populations, adults have the opportunity to attain the same fluency level as those who had a head start.

In the study, many learners who began learning their second language after the age of 20 performed just as well, or better, on a difficult language assessment than native-speakers. Though, on average, older learners have a much harder and longer road to reaching true fluency, it is still a realistic goal.

Data even suggests that adults can learn better and more quickly than children do if given the same opportunities. However, it remains much more complicated to reach levels high enough to pass for a native speaker. In just a year of studying, adult learners can reach capable, fluent levels. Imagine what can be done in 5 or 10 years!

As with many things, reaching true fluency in the complexities and subtleties of a language can only be achieved over time and with dedication, regardless of age or lifestyle. However, to reach this destination, you first must understand it. What exactly does fluency look like?

What Does Fluency Look Like? 

To understand how to reach high fluency levels, you must first fully understand what it means to be fluent. The Common European Framework of Reference for Languages (CEFR) is a widely recognized standard used around the world. Levels are broken down as follows:

A1At this level, speakers can use very basic and familiar phrases and can introduce themselves giving basic personal details. Interactions are simple and only possible if speech is slow and clear.
A2Speakers at this level can understand, describe, and communicate using expressions related to their immediate environment, like topics on basic personal information or geophagy.
B1Speakers at the B1 level can understand and produce speech and text on familiar topics encountered at work, school, or during leisure activities. They can also discuss dreams, hopes, and ambitions. 
B2Can understand the main point of complex text on concrete and abstract topics and can produce simple and clear text on a wide range of topics. Speakers at this level can easily and spontaneously interact with native speakers.
C1At this level, learners can understand long, demanding texts, express themselves fluently and effectively in social, academic, and professional environments.
C2At the highest level of fluency, learners can understand virtually anything they see or read and express themselves fluently and with precision. They can also understand subtleties and complexities in speech and written text.
C2 Proficiency speaking test – Derk and Annick | Cambridge English

Now looking at how “well” adults can learn depends on what the goals of the speaker are. Are they learning for travel and only need basic phrases to get by?

Do they have French family members and want to be able to naturally interact with them? Each goal falls into different CEFR fluency levels, and therefore different levels of effort.

The Best Way to Learn a Language for Adults

To learn effectively and efficiently, a learner must first be able to set a realistic goal for themselves. Once they have done so, hard work and effort will be required. Nothing worthwhile comes naturally, and that applies to learning a second language.

Looking at how children acquire their first language can lend huge insight into best practices for adults. For that reason, we have formed this list on the best way to learn a language, carefully considering the acquisition process in children and adapting it to realistic tasks for adults. To begin with, consider these things:

  • Comprehensible Input: Though children may not understand everything they encounter when it comes to speech or reading, they are still able to reach a level of understanding. Using comprehensible input, adult learners should focus on meaningful interactions and not form or grammar mistakes.
  • Immersion: Children acquire language through constant exposure. Without translating, natural connections are formed between symbols and the words that they represent. Adults should aim to immerse themselves, watching movies, listening to music, or reading as often as they possibly can.
  • Language Partner: Children advance so quickly because of nurturing parents who gently correct mistakes and converse with them in their target language. To try to replicate this, adults should consider getting a penpal or language tutor. The more meetings you can book, the better.

Of course, there are other things as well. While the few insights listed above are helpful, some things that a child comes by naturally must also be considered.

What Comes Naturally

Whether it is the natural progression that a child has towards language or the environment and years of preparation a child has naturally, there are things that can be learned. Consider these things:

  • Natural Progression: Children progress through language naturally, learning grammar structures when they are ready. This is difficult to achieve in a classroom as progression is uniform. Adults should therefore aim to learn structures that are directly related to their current goals and interests.
  • Self-analysis: Children learn a language in stress-free, low-pressure environments. Anxiety has been proven to affect how well learners receive and retain information. Adults should aim to create meaningful, low-stress situations where they can use their target language, like at a language club.
  • Preparedness: Children are exposed to years of comprehensible input before they feel ready to produce any speech themselves. Adults should allow themselves the same luxury by throwing off the pressure of producing text and speech immediately at the start of learning.

If adult learners try to replicate these processes as often and closely and they can, language learning will become much more natural and effective. Applying proven methods and skills seen in children allows adult learners to learn well and reach their goals more efficiently.

How Long Does It Take to Become Fluent?

If you have set a language learning goal for yourself, it is natural to wonder how long it will take to get there. There is no obvious answer to this question, as it hinges on many factors, including the difficulty of the language, your fluency level goals, and the amount of time you have or want to dedicate.

All these subjective factors directly affect your language learning process. For this reason, we must look to other benchmarks to help better understand the length of time required to master a language. Children are allotted unlimited time and have low expectations for themselves, while in the case of adults, it is quite the opposite.

Looking to US diplomats for guidance is a good place to start. The Foreign Service Institute (FSI) provides training for State Department employees and provides a language guide outlining estimated time frames for reaching working level proficiency in a language. Languages are divided into categories as follows:

Category ILanguages in this category are similar to English and, on average, require 24-30 weeks, or 600-750 hours of class time, to reach a working level proficiency. Spanish, French, Italian, Danish, Dutch, and Swedish all fall into this category.
Category IILanguages in this category are more difficult, requiring on average 36 weeks, or 900 class hours, to reach proficiency. German, Malay, Indonesian, and Haitian Creole make up this category.
Category IIICategory III are languages considered as “hard languages,” with significant cultural and linguistic differences from English. On average, they require 44 weeks or 1100 hours of class. Some languages include Albanian, Farsi, Hebrew, Greek, Polish, Turkish, Thai, Urdu, Vietnamese, and more.
Category IVThe highest category, labeled as “super-hard languages,” requires on average 88 weeks or 2200 class hours to reach proficiency. Arabic, Chinese, Japanese, and Korean all make up this category.

Though this list can be helpful to generalize the time needed, it may be more realistic to view time in daily chunks. The time you put into learning is what you will get out of it. So how often and for how long should a learner spend on studying to achieve a proficient level?

How Long Should I Study Every Day? 

It is clear that the more time you spend on any practice-based task, the more quickly you will advance in your skills. Learning a language is no exception to this, and while we can provide estimations, it is up to you to determine what is most conducive to your goals and lifestyle.

Across the board, experts agree that cramming is the enemy of success and knowledge retention. For this reason, instead of spending five hours once a week practicing your language skills, it is much more effective to space out your work into smaller chunks throughout.

Furthermore, many working adults just simply do not have the time for hours of work a day on learning a language. Setting unrealistic and strenuous goals for yourself may result in a loss of motivation and the abandonment of your goals. Furthermore, after hours of studying, studies suggest you may even stop retaining information.

So what is the ideal timeframe for successfully advancing in your language goals? Experts at the European Conference on Ambient Intelligence suggest that even just 5 to 15 minutes of “microlearning” a day can make a difference. Other experts believe 30 minutes a day is the ideal window for acquiring a skill.

Previous Knowledge

Learners who have previous knowledge of a language hold a strong advantage over those starting from scratch. Even if it has been years since a student has used or been exposed to their target language, the experience gives a huge advantage over learners who are encountering the language for the first time.

The previous knowledge is advantageous for many reasons, including:

  • If a language uses a new character system, like Arabic, students may only need a refresher instead of having to learn the entire system from scratch.
  • Previous experiences mean the learner’s ear is a tune to the sounds, intonation, and flow of a language, facilitating pronunciation the second time around.
  • Learning new vocabulary words and retaining the information is much more likely when a learner has already encountered them.

Learners who are one step ahead in their experience may not require as much time daily to reach a proficient level but still should push themselves to work and study regularly. However long you may spend a day studying your language, it is important to be consistent and vigilant if you are serious about achieving your goals.

Final Talking Point on How Well Adults Can Learn a Second Language

Younger populations hold the advantage over adults in learning a second language well and achieving a level of proficiency. For children, it is natural to absorb and learn information. However, this should not discourage adult learners. Instead, it should serve as a guide for facilitating their language acquisition.

Adults are biologically and cognitively capable of mastering a language, despite some challenges from aging. However, lifestyle is a huge deterring factor.

For this reason, adults who are serious about their goals must find ways to mirror the language acquisition process children use by immersing themselves and using their target language as much as possible.

Though adults may have to work harder and longer to achieve the same results children see when learning a language, it is not an impossible task, to say the least.

Adults can reach the same mastery and fluency levels as a native speaker if they are only willing to find the time, put in the effort, and advance daily towards their goals.

Additional Sources: 

https://elearningindustry.com/adults-learn-a-second-language-struggle

https://www.britishcouncil.org/voices-magazine/can-we-learn-second-language-we-learned-our-first

Jackie Booe

Jackie Booe is a licensed teacher for elementary through high school in 3 states. She is a former adjunct professor at the undergraduate level and certified to teach elementary, secondary English, and English Language Learners. She was a mentor for many education interns, has taught and coordinated professional development for teachers and educators, and professionally tutored in a multitude of subjects.

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