Danish children struggle to learn their vowel-filled language – and this changes how adult Danes interact

Danish children have trouble learning their mother tongue, and this changes the way adults interact with them, argue researchers Morten Christiansen and Fabio Trecca in this fascinating article from The Conversation.

Danish children struggle to learn their vowel-filled language – and this changes how adult Danes interact
The Puzzle of Danish is a project based at Aarhus University. Photo: Fabio Trecca/Creative Commons

Denmark is a rich country with an extensive welfare system and strong education. Yet surprisingly, Danish children have trouble learning their mother tongue. Compared to Norwegian children, who are learning a very similar language, Danish kids on average know 30% fewer words at 15 months and take nearly two years longer to learn the past tense. In “Hamlet,” William Shakespeare famously wrote that “something is rotten in the state of Denmark,” but he might as well have been talking about the Danish language.

We are a cognitive scientist and language scientist from the Puzzle of Danish group at Aarhus University and Cornell. Through our research, we have found that the uniquely peculiar way that Danes speak seems to make it difficult for Danish children to learn their native language – and this challenges some central tenets of the science of language.

Two spectrograms with the one for Danish a nearly continuous bar and the one for Norwegian shows sharp breaks.

A visual depiction of the words for ‘smoked trout’ spoken out loud in Danish (top) and Norwegian (bottom). Note how in Danish the two words completely melt into each other. Fabio TreccaCC BY-ND

Why is Danish so hard?

There are three main reasons why Danish is so complicated. First, with about 40 different vowel sounds – compared to between 13 and 15 vowels in English depending on dialect – Danish has one of the largest vowel inventories in the world. On top of that, Danes often turn consonants into vowel-like sounds when they speak. And finally, Danes also like to “swallow” the ends of words and omit, on average, about a quarter of all syllables. They do this not only in casual speech but also when reading aloud from written text.


The difficulty of Danish is no secret in Scandinavia, as seen in this clip from a Norwegian comedy TV show.

Other languages might incorporate one of these factors, but it seems that Danish may be unique in combining all three. The result is that Danish ends up with an abundance of sound sequences with few consonants. Because consonants play an important role in helping listeners figure out where words begin and end, the preponderance of vowel-like sounds in Danish appears to make it difficult to understand and learn. It isn’t clear why or how Danish ended up with these strange quirks, but the upshot seems to be, as the German author Kurt Tucholsky quipped, that “the Danish language is not suitable for speaking … everything sounds like a single word.”

Kids learn later, adults process differently

Before we could study the way Danish children learn their native language, we needed to figure out whether the peculiarities of Danish speech affected their ability to understand it.

To do this, our team sat Danish two-year-olds in front of a screen showing two objects, such as a car and a monkey. We then used an eye tracker to trace where the kids were looking while listening to Danish sentences.

When the children heard the consonant-rich “Find bilen!” – which sounds like “Fin beelen!” when spoken and means “Find the car!” – the toddlers would look at the car quite quickly.

However, when they heard the vowel-rich “Her er aben!” – which sounds like “heer-ahben!” and means “Here’s the monkey!” – it took the kids nearly half a second longer to look at the monkey. In this vowel-laden sentence, the boundaries between words become blurry and make it harder for the toddlers to understand what is being said. Half a second may not seem like much, but in the world of speech it is a very long time.

A woman speaking to her young child.

Children learn language by listening to people speak, but the quirks of Danish make this a harder process compared to other languages. Thanasis Zovoilis/Moment via Getty Images

But does the abundance of vowels in Danish also make it more difficult for children to learn their native language? It turns out that it does. In another study, we found that toddlers struggle to learn new words when these words are sandwiched between a lot of vowels.

Danish children do, of course, eventually learn their native tongue. However, our group has found that the effects of the opaque Danish sound structure don’t go away when children grow up: Instead, they seem to shape the way adult Danes process their language. Denmark and Norway are closely related historically, culturally, economically and educationally. The two languages also have similar grammars, past tense systems and vocabulary. Unlike Danes, though, Norwegians actually pronounce their consonants.

In several experiments, we asked Danes and Norwegians to listen to sentences in which either a word was deliberately created to sound ambiguous (like a word halfway between “tent” and “dent”) or the meaning of the whole sentence was unusual (such as “The goldfish bought a boy for his sister”). We found that because Danish speech is so ambiguous, Danes rely much more on context – including what was said in the conversation before, what people know about each other and general background knowledge – to figure out what somebody is saying compared to adult Norwegians.

Together, these results indicate that the way people interpret language is not static, but dynamically adapts to the challenges posed by the specific language or languages they speak.

A man motioning with his hands as he explains something to another person.

Adults who speak Danish rely more on contextual clues – like what they talked about earlier and what they know about the other person – than speakers of other languages. Thomas Barwick/Stone via Getty Images

Not all languages are the same

There has been a longstanding debate within the language sciences about whether all languages are similarly complex and whether this might affect how people’s brains learn and process language. Our discovery about Danish challenges the idea that all native languages are equally easy to learn and use. Indeed, learning different languages from birth may lead to distinct and separate ways of processing those languages.

Our results also have important practical implications for people who are struggling with language – whether because of a single traumatic event like a stroke or due to genetic and other long-term factors. Many current interventions meant to support language recovery are based on studies in one language, usually English. Researchers assume that these interventions would apply in the same way to individuals speaking other languages. However, if languages vary substantially in the way they’re learned and processed, an intervention that might work for one language might not work as well for another.

Linguists have looked at differences between languages before, but few have been concerned with the possible impact that such differences may have on the kind of processing machinery that develops during language learning. Instead, much of the focus has been on searching for universal linguistic patterns that hold across all or most languages. However, our research suggest that linguistic diversity may result in variation in the way we learn and process language. And if a garden-variety language like Danish has such hidden depths, who knows what we’ll find when we look more closely at the rest of the world’s approximately 7,000 languages?

Morten Christiansen is the William R. Kenan, Jr., Professor of Psychology, Cornell University, and Fabio Trecca is Assistant Professor of Cognitive Science of Language, at Aarhus University. 

This article was first published in The Conversation

Member comments

  1. Another difference, not mentioned, is that Danes do not move their faces (mostly their lips) much when speaking. So you cannot rely on visual clues for ‘hey, what vowel was that I just heard’ in the same way you very much can when listening to Swedes and Norwegians. (This is an over-generalisation — good luck trying to understand the people of Trelleborg, Sweden using visual clues 🙂 — but still I think broadly true for all three places.) I wonder if this makes a difference?

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Why do Danes love the Danish flag so much?

Danes have a love for their flag bordering on obsession — not only is it a symbol of patriotism for national holidays and football games, the Dannebrog is also the default theme for birthday parties (yes, even for children) and is a staple for celebrations of any sort.

Why do Danes love the Danish flag so much?
A spectator holds a Danish flag during the match between Caroline Wozniacki of Denmark and Elise Mertens of Belgium. REUTERS/David Gray

Most Danish households have a small arsenal of flags in various sizes to suit all of life’s most Danish occasions, and there’s a year-round section of Dannebrog party supplies in most grocery stores. Don’t forget the Dannebrog garlands for your Christmas tree, either.

But how did the Danish flag develop this cult-like devotion? (Other than apocryphally falling from the sky in 1219, of course.) According to Torben Kjersgaard Nielsen, an historian at Aalborg University and author of a book on the Danish flag, the Dannebrog was strictly a symbol of royalty and the military through the 18th century. But in 1801, celebrated actor H.C. Knudsen stirred up patriotic sentiment with performances of songs and poems honouring Denmark, always staged in front of a Dannebrog.

“From then on, the flag grew to become a popular flag, pointing to allegiance to the kingdom (fatherland) rather than the monarch himself,” Kjersgaard Nielsen told The Local. Golden Age poetry praising Denmark’s ancient heritage natural beauty further swelled national pride, to the Dannebrog’s benefit.

READ MORE: Denmark’s Dannebrog ‘fell from sky’ 800 years ago today 

A child counts the number of Danish flags on a cake to see how old the birthday girl is. Photo: Lars Plougmann/Flickr.

By the 1830s, Danes were flying the Dannebrog so much it became a source of concern for the autocrat king Frederik VI—“flags were at his time starting to be used as markers and symbols of independence and democracy” as in France’s July Revolution, Kjersgaard Nielsen explained. In 1833, Frederik VI forbade private use of the Dannebrog over the government’s objections.

But even the king couldn’t keep the Dannebrog down. “The popular use of the Dannebrog surged during the war with Schleswig-Holstein in 1848-50 and the personal uses may have developed from there,” Kjersgaard Nielsen said. “It was used hanging as a garland on Christmas trees (German tradition, in fact), and it was used to celebrate happy events, weddings, anniversaries and probably also birthdays.” After it became impossible to enforce, the ban was lifted in 1853 and Danes have proudly hoisted the flag at every opportunity since.

Today, the flag represents joy and celebration as well as a love for country, Kjersgaard Nielsen said. “There is a debate going on in Denmark – and it has for a long time now – where some people argue that the flag is xenophobic and overly nationalistic; others – the majority – seem to understand that this is just one of the manifold uses of the flag and that waving the flag does not mean supporting right wing policies.”

READ MORE: Danish policies ‘fuel fear and xenophobia’: UN 

Last month, you likely saw the Dannebrog plastered on studenterkørsel—the party buses ferrying tipsy gymnasium graduates from house to house—and on storefront windows advertising sales. It’s never too early to start collecting for next year’s Flag Day, or Dannebrogsdag, on June 15th.