An international research team led by the University of Zurich has studied the speed and flow of speech production in languages used across the globe. The experts found that speakers stumble over nouns much more frequently than verbs, even though verbs are often more complex.
During natural speech, people unconsciously pronounce some words more slowly than others. The researchers found that speakers often pause and utter sounds like “uh” or “um” in anticipation of nouns.
The slowdown effects provide insight into how the human brain sorts out language and referential information, and the study findings indicate that that this cognitive process is universal.
To investigate the occurrence of slowdown effects in speech production, the team analyzed thousands of recordings of speakers from linguistically and culturally diverse populations including the Amazon rainforest, Siberia, the Himalayas, and the Kalahari desert. The researchers also analyzed spontaneous speech recordings in English and Dutch.
The experts focused on slowdown effects before nouns and verbs, measuring the speed of pronunciations and noting whether or not the speakers paused.
“We discovered that in this diverse sample of languages, there is a robust tendency for slowdown effects before nouns as compared to verbs,” explained the study authors. “The reason is that nouns are more difficult to plan because they’re usually only used when they represent new information.”
If a noun does not represent new information, it is usually replaced with a pronoun. Verbs, however, are typically used regardless of if they represent new or old information.
“We found that English, on which most research is based, displayed the most exceptional behavior in our study,” said study co-author Professor Balthasar Bickel. Therefore, the authors explained, it is important to include a broader range of dialects in language processing research, including rare and endangered languages from around the world.
The study contributes to a deeper understanding of how languages work in their natural environment. This is especially valuable given the communication challenges of the digital age, as artificial systems do not produce the natural flow of human language.
Future research should be focused on the information value of words used in conversation, and how the brain reacts to differences in these values.
The study is published in the Proceedings of the National Academy of Sciences.