Researchers have found that monkeys combine calls to make them meaningful in the same way that humans do.
It is hoped the St Andrews University study will provide fresh insights into the evolution of human language.
The researchers recorded the alarm calls of putty-nosed monkeys in Nigeria and noticed them combining noises to apparently convey different meanings.
It had been thought monkeys could only create new sounds to communicate rather than combining existing noises.
Scientists had thought that combining calls, as a human trait, only came about because the repertoire of noises had become so large.
However, the putty-nosed monkeys only have a small number of sounds, according to scientists.
Dr Klaus Zuberbühler, of the university's school of psychology, said: "Our research has revealed some interesting parallels in the vocal behaviour of forest monkeys and this crucial feature of human language.
"At some point, according to the theory, it became more economical for humans to combine existing elements of communication, rather than adding new ones to a large repertoire.
"This is based on the notion that signals would be combined only once the number of them had grown sufficiently.
"Our research shows that these assumptions may not be correct."
In 2006, researchers from St Andrews found that monkeys produced different series of alarm calls in order to distinguish which predator they are responding to.
The latest research provides evidence that the various calls may contain at least three types of information - the event witnessed, the caller's identity, and whether he intends to travel, all of which were recognised by other monkeys.