Glasses with live subtitles

Glasses for the deaf and the hard of hearing. It sounds strange, but it is currently in full development. These glasses, called SpraakZien (SpeechView), provide the wearer with live subtitles during a conversation, while allowing for continued eye-contact between the speakers. Four Leiden students of Linguistics are carrying out experiments with the glasses.

Speech recognition

For a hearing person, the glasses may be a gimmick, but for the deaf and the hard of hearing it is a godsend. The wearer sees what their conversation partner is saying appear as text in the air, projected at a virtual distance of approximately three metres. The glasses have a wireless connection to a microphone. Speech recognition software transforms the captured sounds into text, which is then reproduced by the glasses. The (transparent) glasses are at present still somewhat unwieldy.


The idea for SpraakZien occurred in 2010 outside Leiden University, when physicist Michiel van Overbeek, specialist in sound, suddenly developed a hearing condition. He started brain-storming and came up with the glasses. In order to develop his idea, he started the firm OorZaak, together with Wilfried Claus and Barend Nieuwendijk. Nieuwendijk: ‘We combine three existing technologies: video glasses, mini-microphone and speech recognition software. These technologies are all developing rapidly. We also want the software to run on smartphones; at present you still need a laptop.’ The Sudden Deafness Foundation (Stichting Plotsdoven) was enthusiastic about the initiative and called out for test subjects.

Theory and practice

At present, the technology is still very much in the testing stage. And this is where Leiden comes in. Because the theory is of course beautiful, but do the glasses really work as expected? Are they really useful to people with hearing problems? This is how OorZaak ended up contacting the Linguistics Department, where students are already learning about psychology and neurolinguistics, and where they also have experience with experimental linguistics.


The experiments fall under the responsibility of neurolinguist Prof. Niels Schiller and phonetician Prof. Vincent van Heuven from the Leiden University Centre for Linguistics (LUCL). In the phonetic lab at the Lipsius Building, four students are testing deaf and hard of hearing subjects. The test subjects are asked to repeat words and answer questions about a story told by the students, once with the glasses, and once without. The reactions are enthusiastic, but also critical, according to the students. ‘There is still much room for improvement. Talking with one person is OK, but how does it work at a crowded, noisy birthday party?’ Nonetheless, the target group does see the product’s potential: ‘Some people have become isolated as a result of their deafness; this is a way to break out of this isolation.’

Further optimisation

The students expect to complete their experiments around 15 December. They will then start processing the data and write a joint article about the results. Barend Nieuwendijk expects the development phase of the glasses to take some more time. ‘With what we have so far, we can already help many people, but we are still looking at years of optimising the glasses.’

(3 December 2012/Coen van Beelen)

See also

Health across the Human Life Cycle is a profile theme of research at Leiden University.

Studying in Leiden


Linguistics (research)

Last Modified: 19-08-2013