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A cap with electrodes is used to document brain activity during different language tests. The image is from a research project that tests synchronisation activity in pre-school children.

Do you have an ear for languages? It may be related to how you perceive the rhythms

How our brain processes language can also tell us something about other characteristics, advantages, or challenges that we have.

COMMUNICATIONS ADVISER
Presented by: NTNU - Norwegian University of Science and Technology
Published

We begin to hear speech when we are in the womb, and the first thing a foetus perceives is the rhythm of language. 

At NTNU's language laboratory, researchers have made important discoveries and have often challenged established theories.

“Some people find the beat straight away and are very good at keeping in time, while others are more hesitant," PhD candidate Guro S. Sjuls says.

Researcher Guro S. Sjuls is the first author of a new article, which is linked to synchronisation to rhythm in language. An analysis of people’s ability to tune into the rhythm of language and what this entails has recently been published in Communications Psychology.

Some people find the beat straight away, others take a little longer

The researchers have implemented and analysed the Speech-to-Speech Synchronization (SSS) test. This is a seemingly simple method used to measure people’s ability to synchronise their speech or language with an external speech signal. Synchronisation refers to two or more things working harmoniously together.

The test involves participants hearing syllables and having to continuously reproduce the rhythm of the syllables. 

The syllables the participants hear are played at a frequency of 4.5 hertz. This is the average syllabic rate across languages. This simply means that there is room for four to five syllables per second in a single sequence.

“Some people find the beat straight away and are very good at keeping in time, while others are more hesitant. This enables us to place them into two groups,” Sjuls says.

The two groups are:

  • High synchronisers - these are good at synchronising to the rhythm of speech they hear.
  • Low synchronisers - these are not as good at synchronising the rhythm of speech.

The SSS test involves participants synchronising their speech in relation to pre-recorded speech.

“Interestingly, we found that this ability is not evenly distributed in the Norwegian population. Some individuals naturally synchronise their speech with the external signal, while others do not," Sjuls says.

She mentions that previous research has shown that this difference remains consistent over time. This suggests that the ability to synchronise is a stable characteristic.

Different brain structures give different abilities

Professor Mila Vulchanova has spent her whole life studying language comprehension, language development, and how the brain works to handle language.

The two groups have significant differences in brain structure and function.

“High synchronisers have a stronger connection between the part of the brain that perceives language and the part that produces language,” Professor Mila Vulchanova says.

She has run the language laboratory at NTNU for nearly 20 years.

The two groups also perform differently on different tasks. High synchronisers learn the sound of new words significantly better than low synchronisers. 

More importantly, in high synchronisers, there are strong associations between the ability to synchronise, brain-to-language signal synchronisation, and connections between linguistic networks.

A language bridge in the brain

The arcuate fasciculus plays an important role in the brain’s ability to process and learn language.

It contains both long and short fibres and acts as a sort of bridge between the posterior (temporal) and frontal areas of the brain. The ability to learn new words is dependent on efficient and rapid communication between the temporal and frontal areas.

The arcuate fasciculus has a curved shape and is usually larger in the left hemisphere than in the right.

The arcuate fasciculus plays an important role in the brain’s ability to process and learn language.

A previous study from 2019 has shown that people belonging to the high synchronisers group generally have an arcuate fasciculus that is more strongly lateralised to the left. They thus have a larger structure in the left hemisphere.

Some theories on the origin of language see connections between the development of stronger left lateralisation of the arcuate fasciculus and the development of the ability to produce and use language in humans compared with our close relatives, the primates. 

May be innate

The SSS test has previously been used for English, German, Spanish, and Mandarin speakers. Now, the researcher team have investigated whether the test can also be used for the Scandinavian languages. 

Their findings show that it can: Norwegian speakers can also be divided into high and low synchronisers.

“Our study supports that the test could reflect universal language user traits,” Sjuls says.

The words and syllables that the test participants heard were synthesised from Swedish and English. The study has shown that the varying ability to synchronise also applies to Norwegian native speakers. Furthermore, the study shows that this skill is not dependent on the type of language stimuli used for testing.

“In other words, this ability is probably not dependent on language experience. The ability to synchronise may be innate, and it can also be speculated whether this ability is related to language acquisition and how well individuals are equipped to learn language,” Vulchanova says.

The degree to which individuals can synchronise their own speech to a series of syllables reflects brain differences. These individual differences have implications for the ability to process and learn sound patterns in language.

An important tool in future research

The researchers conclude that the test has the potential to be a reliable tool for future research. The findings provide opportunities for further research exploring synchronisation abilities across a broader range of languages and linguistic characteristics.

The results are promising with regard to understanding individual differences in brain biology that support the links between auditory and motor functions. 

These connections play a crucial role in language because they form bridges between the sounds we perceive and the plans for activating the language organs such as lungs, vocal cords, mouth, and tongue.

“Our next step is to find out whether or not the ability to synchronise is innate, and whether there are any factors that affect it,” Sjuls says.

“We can get clearer answers about whether the ability is innate by studying newborns, for example," Vulchanova says.

She mentions that in an ongoing EU project, they are also looking at whether synchronisation activity in the brain can be linked to and predict language skills in Norwegian preschool children.

How the brain works

The main part of the brain is called the cerebrum and consists of white matter and grey matter. Grey matter is the outermost part. These two substances form the main components of the central nervous system.

The cerebrum is divided into two halves called hemispheres. The two hemispheres communicate with each other through the corpus callosum, which acts as a signal bridge between the two hemispheres.

The two hemispheres have different functions. Practical and logical functions, such as speaking, are controlled by the left hemisphere.

Each hemisphere is divided into four lobes, and each lobe works in pairs and is mirrored in the opposite hemisphere.

  • The frontal lobe is responsible for short-term memory, and ensures that several ideas can be simultaneously assessed in relation to each other. Among other things, the frontal lobe is important for converting thoughts into words and speech, and cognitive control.
  • The parietal lobe is important for processing sensory impressions, perception of movement and in connection with reading and mathematical tasks.
  • The temporal lobe processes auditory impressions and music. The area under the temporal lobe is important for memory.
  • The occipital lobe contains a visual processing centre ensuring that visual impressions are compared to memories stored in the brain, enabling visual impressions to be processed and assessed.

Reference:

Sjuls et al. Replication of population-level differences in auditory-motor synchronization ability in a Norwegian-speaking population, Comminications Psychology, vol. 1, 2023. DOI: 10.1038/s44271-023-00049-2

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