There is a long-standing debate in cognitive science about whether human syntax is a unique, all-or-nothing gift or a gradual evolutionary development seen in other species. While humans possess a three-merge capability for infinite expression, many animals display one-merge combinatorial systems that challenge our definitions of uniqueness.

We dive into three major theories: the computational view of processing power, the surface structure view of limited lexicons, and the deep structure view of event perception. By looking at the alarm calls of putty-nose monkeys and the complex pant hoots of chimpanzees, we see how meaning is encoded and modified through systematic vocal combinations.

• One-merge systems allow animals to combine two individual meaning units into a single call.
• Chimpanzees encode social status, age, and b ...