  The analysis of thousands of time series in different languages reveals that
word usage presents oscillations with a prevalence of 16-year cycles, mounted
on slowly varying trends. These components carry different information: while
similar oscillatory patterns gather semantically related words, similar trends
group together keywords representative of cultural and historical periods. We
interpreted the regular oscillations as cycles of interest and saturation,
whose behavior could be captured using a simple mathematical model. Driving the
model with the empirical trends, we were able to explain word frequency traces
across multiple languages throughout the last three centuries. Our results
suggest that word frequency usage is poised at dynamical criticality, close to
a Hopf bifurcation which signals the emergence of oscillatory dynamics.
Crucially, our model explains the oscillatory synchronization observed within
groups of words and provides an interpretation of this phenomenon in terms of
the cultural context driving collective cognition. These findings contribute to
unravel how our use of language is shaped by the interplay between human
cognition and sociocultural forces.
