You've probably never heard of it by name, but there's a language on Earth more popular than Mandarin, more widespread than English, and more universal than interpretive dance.
It isn't spoken, and it isn't viewed.
It's smelled.
I'm talking about terpenes—a multipurpose class of chemical compounds that can be used to communicate both within and across species.
They're used in all kinds of ways, from hungry eavesdropping microorganisms to brief back-and-forth conversations between creatures you would never think would be up for a chat.
All a molecule has to do to be considered a terpene is have the right structure.
They're made up of multiple subunits of an organic molecule called isoprene, which has five carbon atoms.
These subunits can be arranged in a line, or form rings, or both, leading to a diverse collection of over 30,000 known compounds.
Because it's so broad a label, terpenes can have lots of different biological functions—like as vitamins, hormones, or part of the immune system.
They're also a really common source of scents in plants—you might've heard people talk about terpenes as the chemicals that give different strains of cannabis different aromas, and they're responsible for the scent of things like peppermint and fir trees.