Monkeys can speak basic grammatical language

Campbell’s monkeys appear to combine the same calls in different ways, using rules of grammar that turn sound into language.

For example, male monkeys called “boom boom” to gather other monkeys to them, but “boom boom krak-oo krak-oo” meant that a tree or branch was about to fall. Adding a “hak-oo” to that sequence turned it into a territorial warning against stray monkeys from neigboring groups. Multiple “krak-oo” calls added to an original “krak” meant not only that a leopard was in the area, but that it posed an immediate threat.

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