Tone gives the listener clues

In Swedish, the tone at the beginning of a word indicates how the word will continue. The listener can guess how the word will be inflected without even thinking about it. Wallenberg Academy Fellow Mikael Roll will be mapping the structures in the brain behind this phenomenon.

Mikael Roll

Associate Professor of Linguistics

Wallenberg Academy Fellow 2014

Institution:
Lund University

Research field:
Interaction in the brain between linguistic information of various kinds, such as intonation and grammar.

Listen to the words “ringer” (rings) and “ringde” (rang). The stem of the words is the same, and the “i” is pronounced as sharply and for the same length of time in both cases. But listen carefully. In “ringde”, the tone is a little higher at the beginning of the word. As soon as the stem has been uttered, the listener knows that the word will end in the past form, rather than the present.

“This applies to virtually all Swedish words. My research has shown that we do this quite sub-consciously when we listen to someone talking. These small tonal differences tell us how the word will end, whether it is singular or plural, what gender, and how verbs will be conjugated,” explains Mikael, who researches at the Centre for Languages and Literature at Lund University.

Another example of the relationship between tone and grammar is that tone reveals whether a clause is the main clause or a subordinate clause. Listen to the sentences “Pelle kommer inte, sa jag” (“Pelle’s not coming, I said”), and “Jag sa att Pelle inte kommer” (“I said that Pelle isn’t coming”). The name “Pelle” has a higher tone in the first sentence, where the name is used in the main clause, than in the second, where it forms part of a subordinate clause.

Use of tones varies between languages

Not all languages work like this. Broadly speaking, the world’s languages can be divided into three categories: Tone can impart meaning, as in Chinese. Words can be given an entirely different meaning merely by changing their tone. In other languages, such as English, tone has no influence on meaning at all. Swedish lies somewhere in between. We have some 200 pairs of words whose meaning depends on the tone used to say them, for example the two ways of saying the word “anden” (“the spirit” or “the duck”). But we also have this clear link between tone and grammar, which is Mikael’s research field. There are languages with similar systems, but specifically for Swedish, he has managed to isolate tones with specific grammatical functions.

Combining methods give clear pictures

Mikael will be using various imaging techniques to map the neural pathways and networks in the brain that are involved when we predict grammar with the help of tone. While subjects listen to speech, he will be studying their brains using a number of methods. Electroencephalography (EEG) makes it possible to record electrical activity in the cerebral cortex with extreme precision in time, down to milliseconds. This time precision cannot be achieved using magnetic resonance imaging (MRI), but on the other hand, MRI does give very clear images of active areas of the brain. The best approach is to combine the two methods, and Mikael has just purchased and begun testing EEG equipment that can be used inside the MRI scanner.

“It’s pretty cool actually, being able to insert a whole load of electronics in a strong magnetic field. And it works really well – we have obtained high-quality data.”

A third imaging method is called diffusion tensor imaging (DTI), and records the flow of water in the brain. This shows different neural pathways and how they cross each other.

Learning changes the brain

Mikael is working with researchers in medicine and chemistry who have developed a method of studying changes in the brain right down to cell level. He will use it to examine people who learn Swedish as a second language. He wants not only to see which neural pathways they use; he also wants to see the actual physical changes in their brains when they learn to make the connection between tone and grammar.

“We know already that some parts of the cerebral cortex grow when we learn a new language. If we learn more about these changes in the brain, we may be able to find strategies to help victims of brain damage in need of rehabilitation. It is a question of knowing the neural pathways that are normally used, and how to compensate for an injury. I think the connection between tone and grammar may be important here.”

Mikael is leading a research project to develop a computer game for language teaching. It may be possible to develop a similar tool for rehabilitative use.

“Being named a Wallenberg Academy Fellow means that I can build a research team and carry out this major project. We will gain a better understanding of the relationship between tone and grammar in the brain.”

He began his career as a linguist in Mexico. He had gone there to learn Spanish, met his wife-to-be and stayed for several years. He decided to study linguistics, thinking, “I suppose I can always teach”. But he soon became fascinated about the way language works. He is intrigued that we are so unaware of so much of the language system, even though we use it all the time.

Text Lisa Kirsebom
Translation Maxwell Arding
Photo Magnus Bergström