In publica commoda

Press release: How many words does my child know?

No. 215 - 22.10.2019

Universities of Göttingen and Oslo develop vocabulary app "Babylex

How many words does my child know? And how does his or her language develop in the first years of his or her life? These questions are of interest not only to the parents of small children, but also to researchers. Against this backdrop, scientists at the Universities of Göttingen and Oslo have developed the app "Babylex", which enables the early development of small children's vocabulary to be tracked. Babylex estimates the number of words a child knows and a percentage that compares the child's vocabulary with that of other children of the same age and sex. The app is freely available for both Android and iOS devices.


Babylex calculates the information on the basis of a two-minute test in which parents and researchers indicate which of 25 randomly selected words the child already understands or is able to say. The results can be stored on the mobile phone and the development tracked from month to month. Babylex can currently be used on German children aged 18 to 30 months, American children aged 16 to 30 months and Norwegian children aged 16 to 36 months. Other languages will be included in the future.


The app uses Stanford University's free word database (, which contains anonymous vocabulary data from thousands of children. The contents of the database are collected using standard vocabulary sheets where parents indicate which of the 400 to 600 words their child already knows. "Such questionnaires are regularly used in the clinical evaluation of children," explains psychologist Professor Nivedita Mani from the University of Göttingen. Babylex then estimates the number of words that individual children know based on the overlap between the answers entered into the app and the answers in the database.


"Studies with children in Göttingen at our ‘Wortschatzinsel’ show a remarkable correspondence between the vocabulary estimates provided by the app and the standard vocabulary questionnaires, although the app takes much less time to complete," says Mani. More information on the app and its use can be found at, information on the research behind Babylex at



Professor Nivedita Mani

University of Göttingen

Faculty of Biology and Psychology

Georg Elias Müller Institute for Psychology

Goßlerstraße 14, 37073 Göttingen

Phone: +49 551 39-10889