A linguist studying language drift measures semantic shift using cosine similarity. The similarity between a 1950s phrase and modern usage is 0.64. Over 10-year intervals, similarity degrades exponentially by a constant factor each decade. If the decay is consistent, what is the similarity after 30 years?

Mon, 20 Apr 2026 02:52:02 +0000

What happens when language evolves beyond familiar roots? For a linguist measuring semantic shift with cosine similarity, the data reveals a clear trajectory: a phrase from the 1950s holds only 0.64 similarity to today’s modern usage. Applied over consistent 10-year intervals, this decay follows an exponential pattern—meaning meaning gradually shifts as culture and communication transform. After 30 years, the similarity drops significantly: applying a consistent decay factor over three decades yields approximately 0.13 as the semantic equivalence. This silent transformation reflects how words lose precision, gain nuance, or even flip meaning over time. Is this trend capturing attention in the U.S. today? Yes. In the age of digital communication, cultural change, and rapid technological adoption, experts observe growing public and academic interest in how language reveals deeper shifts in thought and society. Discussions around semantic drift cover everything from shifting terminology in media to evolving social values—revealing language as a living, adaptive system. How does this measuring tool actually work? When two phrases are compared across time intervals, cosine similarity calculates the angular distance between their semantic vectors. A score of 1 means identical meaning; a 0.64 score from the 1950s indicates meaningful but distinct interpretation—captured precisely by exponential decay modeling. Each decade, the score diminishes by a consistent factor, revealing not random drift, but a predictable curvature of change. What does the mathematics behind this decay look like? With a multiplicative factor applied every 10 years, starting at 0.64, repeated over three decades (30 years), the full calculation yields a final similarity score of approximately 0.13. This supports the view that word meanings fragment over time, not abruptly—but through a measurable, incremental transformation.