Common bacteria found in soil and water "talk" to each other using a language in some ways as sophisticated as our own, say scientists.
The bugs display a level of "combinatorial" communication previously thought to be unique to humans and certain other primates.
It involves using two signals together to transmit a message that is distinct from them both.
A human example would be the word "boathouse" which does not invoke separate independent thoughts of a "boat" and a "house", but something different - a boathouse.
This type of communication has never been observed before in species other than humans and their closest relatives.
Yet the lowly microbe Psuedomonas aeruginosa appears to be capable of it, using chemicals instead of words.
The bugs exchange dual chemical messages to signal when to produce certain proteins vital for their survival.
By blocking one signal and then the other, scientists found that if the signals are sent separately, the effect on protein production is different from when both are sent together.
Lead researcher Thom Scott-Phillips, from the University of Durham, said: "We conducted an experiment on bacterial communication, and found that they communicate in a way that was previously thought to be unique to humans and perhaps some other primates.
"This has serious implications for our understanding of the origins of human communication and language."
The findings are published in the online journal Public Library Of Science ONE.