foreign accentFor most people who set out learning a new language, the ultimate goal is to achieve an almost native fluency. The keyword in that sentence being ‘almost’. While we may put considerable effort into studying the grammar and vocabulary, there is one small but significant aspect of any language that is hard to grasp: phonetics. The ‘art’ of imitating native sounds is in fact the most difficult part of language learning. Those who are currently in the process of learning  a new language and find themselves struggling to grasp the grammar or are faced with the arduous task of memorizing a vast vocabulary may think this absurd. But in fact, there are physical restrictions that make it so hard – or even impossible – to achieve a perfect foreign pronunciation.

Why do people have accents? The answer, naturally, lies in the variety of sounds in different languages. Anyone who has ever tried to speak a language that differs greatly from their native tongue knows how challenging this is. Every language consists of small sound elements (called phonemes) that, when strung together, make up each word’s unique pronunciation. Examples for language-specific sounds that foreign speakers find hard to duplicate are the ‘th’ in English (a dental fricative sound), the nasal ‘un’ in French and the German Umlaute ‘ä, ö, ü’.

But why is it so difficult to imitate these sounds? The explanation lies in our brain and its structural and developmental changes as we grow older. Have you ever heard of those ‘windows of super learning’ that allow children to learn with a speed and ease that adults can only dream of? It is often said that it is important to learn languages young and there is in fact a physiological reason to do so. After birth, infants have universal language learning capabilities. As opposed to adults, they can perceive every phoneme in any language and therefore possess the ability to  fully master any tongue – if they are exposed to it. While children by no means are born with the ability to speak all languages, they are born with the ability to learn them. During certain phases of development these abilities are even greater than at any other time in life.

And this is what happens in the brain during “super learning windows of opportunity“: Driven by regulatory genes (which do as their name suggests), the activity of neurotransmitters that support learning (e.g. dopamine and glutamate) increases by as much as 225%. During these phases of increased neural activity, children not only learn faster, certain neurological processes also ensure that they will retain this information long-term. These windows of opportunity are the only time in a human’s life that they will ever become a true master of any language.

For a person to be able to pronounce certain sounds, it is necessary that they be exposed to them before a certain age; afterwards, they not only lose the ability to speak these sounds, but also to hear them. This can be explained as follows: In a child’s (super learning) brain, large parts of the neural capacity are dedicated to the acquisition of language. Later in life, most of these neurons are rerouted, only a small percentage remains and settles in specific areas of the brain. [Language skills become localized in the left brain hemisphere, the process is called lateralization.] If we attempt to learn the sounds associated with another language later in life without having received the proper stimuli as a child, we may find it to be impossible: The responsible networks (or neural connections) never fully developed, or neurons once dedicated to language acquisition have rewired for a different use.

Can you only be fluent if you learn a language as a child?

Does this mean, then, that our attempts to become fluent and (near) native as an adult are in fact futile? This is at least what the physical process involved in language learning seems to suggest. It is still necessary to explore why some adult learners become much more proficient in their pronunciation of foreign languages than others. There are of course famous examples like Arnold Schwarzenegger who, despite living in another country and conversing in its native tongue (their second language) for years, are never able to overcome the (heavy) accent of their native language. Others smoothly adopt the characteristic traits of a second (or third) language if they spent some time among native speakers.

The neurological basis is the same for everyone: Any language acquired after puberty will have to build its synaptual connections in the network established to hold the mother tongue(s) as a child. The pattern mastered in that context therefore affects our level of (spoken) mastery for languages learned later in life. In contrast our vocal tract – the physiological basis for the production of speech sounds – differs in regards to shape and size (of the mouth, throat, tongue, teeth, etc.) for everyone. An accent can therefore be merely a product of a difference in physical production. However, it is also possible that genetics or early life experiences (e.g. exposure to a foreign tongue) play a role in how well we master pronunciation. And lastly, as always, there is motivation. For those who put their mind to it and make a concentrated effort, it is quite possible to adopt an authentic-sounding accent in a foreign language. If you need a goal to work towards: The first time a native tells you they never would have guessed you to be non-native, that is the greatest compliment.


Jenkins, Dr. Orvile Boyd: Why Do People Have Accents? [February 27, 2007]. Retrieved January 25, 2012 from

Language learning by adults (the so-called “second language acquisition”). Retrieved January 25, 2012 from

Why We Need to Learn a Foreign Language Young. Retrieved January 25, 2012 from

Windows of Super Learning Opportunity. Retrieved January 25,2012 from