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Linguists: crimefighters extraordinaire

Rector Magnificus Carel Stolker will retire on 8 February. If there’s one theme running through his career, it’s the links between the University and society. In this series of pre-retirement discussions, Stolker will talk one last time to people from within and without the University. In this first edition: linguists Willemijn Heeren (Leiden University) and Tina Cambier (NFI and IND) on collaboration in applied science.

The trialogue has already been going for a quarter of an hour when something happens that many teleworkers will undoubtedly recognise. Rector Magnificus Carel Stolker makes his excuses, grabs his laptop from the kitchen table and stomps upstairs. While the screen jolts up and down, he looks for a quieter spot on the first floor. ‘Sorry,’ he says again. ‘We’ve got a visitor coming in a minute, so I had to move.’

The discussion takes place on 21 December 2020, the shortest day of a year that seemed to last forever. Whereas on February we proudly celebrated Leiden University’s 445th birthday in a packed Pieterskerk, we now have almost a year of working and studying from home behind us. And that also applies to the big boss of the University, who now only goes to Rapenburg if it’s absolutely essential: if he has to provide a “wet signature”, for instance, i.e. sign a document with a pen. ‘I’d never heard of that before this year, but that kind of signature is sometimes essential for notaries.’

Clockwise from above: Rector Carel Stolker, Tina Cambier (NFI and IND) and Willemijn Heeren (Leiden University).

Proud of variety

Stolker consciously chose two linguists for this first pre-retirement discussion. During the conversation he is visibly and audibly proud of the enormous range of languages that are taught and studied at ‘his’ Leiden University, ‘right down to the Papuan languages.’ But when he talks to others he sometimes realises they are unaware of and thus do not appreciate the value of this variety of languages. ‘They sometimes ask me: “What exactly do you do in linguistics and what’s the point of it?”’

Over to Willemijn Heeren and Tina Cambier to explain. They both work in forensic speech analysis, an applied branch of linguistics that does research for criminal investigations. ‘Take a telephone threat,’ says Heeren, Senior University Lecturer at the Leiden University Centre for Linguistics (LUCL). ‘I study the extent to which the speech material in such a contentious voicemail or telephone tap corresponds with speech material from a suspect, to determine whether it could be from the same speaker. If so, that could form evidence in court.’

Stolker wonders how you go about this. Heeren: ‘We listen to all the ways that speakers differ from one another, such as their voice, their accent and their word choice. But the tricky thing is that even two recordings of the same speaker can differ from each another in many respects, depending on the situation and emotion, for instance. Speech is variable, so you never get the same kind of hard match that you do with DNA research. What I’m now researching is where the most reliable speaker information can be found in the speech signal. Which part of an utterance can we use to best determine whether two recordings are of the same speaker? For instance: is it better to look at stressed or non-stressed vowels?’

Heeren has been working since 2015 with Tina Cambier, who works as a linguist for, among others, the Netherlands Forensic Institute (NFI). ‘I wanted to bring the annual conference of the International Association for Forensic Phonetics and Acoustics (IAFPA) to the Netherlands that year,’ says Cambier. ‘And I knew it would be easier if we had a university on board as co-organiser. I discovered that Willemijn was willing to do that with us.’

Willemijn Heeren: ‘What I’m now researching is where the most reliable speaker information can be found in the speech signal. For instance: is it better to look at stressed or non-stressed vowels?’

Cambier also works for the Immigration and Naturalisation Service (IND), where she investigates whether refugees really do come from war zones by looking at the languages they speak. Here too linguistic expertise is used to solve a societal issue therefore. Cambier: ‘So you see that forensic speech and language research is very broad, and the material that I study is hugely diverse too. Not just foreign languages but slang, WhatsApp messages and lip reading also crop up. Which means we regularly need informants who know a lot about a specific topic. The contacts with Leiden University come in handy.’

Networking while running

Cambier and Stolker are in the same Leiden running group, which is how they got talking. This chance meeting gave a boost to the fruitful collaboration between the NFI, the IND and the University. ‘It helps that we run at the same pace,’ says Stolker. ‘It’s not the fastest pace but it means you have enough breath to exchange a few words.’ Cambier laughs: ‘We run as slowly as each other, although we prefer to say that we run as quickly as each other. That sounds more positive.’ 

Stolker gave Cambier some concrete tips on how to create a long-lasting partnership and encouraged her. This ultimately resulted in a guest lectureship at Leiden University, where she developed the Forensic Speech Science master’s course in 2017. ‘Carel’s enthusiasm really made me persist because I did wonder at times why I had taken on so much extra work,’ says Cambier. Heeren followed the opposite route at around the same time. She mainly works for Leiden University, but since 2018 has also been employed by the NFI for a small part of her time.

These are the kinds of connection that Stolker visibly enjoys seeing. In his period as Rector Magnificus he regularly commented that if you were to ask him the University was there to serve society. Only then would academia be able to help solve the huge challenges facing society, from COVID-19 to climate change and from globalisation to organised crime. ‘Sooner or later excellent scientific research in the entire knowledge chain always proves useful,’ is how he puts it.

Bring people together

These connections are not just between Leiden University and the outside world but also within the University itself. ‘As members of the Executive Board we have a beautiful view of the whole University,’ Stolker said two years ago to the LeidenLokaal blog. ‘This means you see the many opportunities for the people from Archaeology, for example, to work with the legal experts or the historians to work with the social scientists or anthropologists. Bringing people and their disciplines together is one of the many wonderful things about this job.’

Tina Cambier and Carel Stolker got talking while running.

Cambier and Heeren also work at the interface between different disciplines. The Forensic Speech Science course is open not only to students on the Linguistics master’s programme but also to criminology students. ‘How is this interdisciplinary collaboration going?’ asks Stolker. Cambier explains that it is really good fun to have people from different backgrounds in a lecture hall, but that it does cause the odd practical problem too. ‘The study periods of the two faculties aren’t synchronous, for example, which means criminology students sometimes end up facing problems.’

Positive effect of coronavirus pandemic

In Stolker’s term as Rector the University worked hard on what was known in the bureaucratic jargon as ‘harmonisation of educational logistics’. The aim: to ensure that all of the faculties apply more or less the same rules for lecture times. That would make it easier to follow a minor at another faculty, for instance.

‘We managed to partly achieve this, not least thanks to the huge efforts of Vice-Rector Hester Bijl and her team,’ says Stolker. ‘The first things have been solved, which is no mean feat. But it is proving to be more difficult for the minors in particular. Some faculties work with minors that run at the same time as other courses in a semester, whereas others reserve an entire part of a semester for minors that are taught in blocks. And students who follow a minor with in LDE Universities [alliance between Leiden University, Delft University of Technology and Erasmus University, ed.] need no fewer than five cards to get in everywhere. It’s an incredibly complex problem that is due not just to people but more often than not to the systems.’

Students may now receive help from a rather unexpected ally: coronavirus. Stolker: ‘Part of the problem is due to travel time. If you only have a quarter of an hour’s break between your courses, then it’s impossible to get from a building in the centre of Leiden to the Bio Science Park, let alone travel to The Hague, Delft or Rotterdam. But with digital teaching you can. I hope that we will be able to keep this positive effect of the crisis.’

The same is true for Stolker’s retirement itself, during the dies natalis on 8 February. Although only a few people will be present in Pieterskerk, we will all be able to watch the ceremony via the livestream. Even if we have just left a lecture.

Text: Merijn van Nuland
Illustrations: Pirmin Rengers

‘Broad education gives Leiden linguists a head start’

Cambier has noticed that many of her fellow linguists at the IND studied at Leiden University. ‘I don’t think this is coincidence. Linguists students are given a broad education at Leiden University, from Western languages to African Bantu languages. That’s exactly what the IND needs because at one point most refugees come from South Sudan and Sierra Leone whereas at the next they come from South Somalia and they now mainly come from Syria. You need to think on your feet.’

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