Why do uncommon words follow different statistical patterns than common words? Why do these patterns appear universally across languages? And why might language learners or individuals with certain language disorders display the statistics of uncommon words sooner?

This research reveals that these phenomena may stem from fundamental cognitive limits on our brain’s capacity to store and process vocabulary.

The distinct statistics of rare words mark this cognitive boundary. We argue that these limits are fundamental to human cognition, so the resulting statistical patterns are universal.

Understanding the link between mind and language structure offers insights into linguistic evolution, cognitive science, and the development of more human-like artificial intelligence.