Do animals secretly talk to each other when people aren't looking, like in the movies? Well, the answer is no. In fact, there's nothing secret about it, many animals talk to each other all the time, even when humans are looking!
For example, take the Vervet monkey.
It's a species of monkey that lives partly in open, grassy savannas. Researchers have found that you can tape record the various calls made by Vervet monkeys and play them back one at a time. In other words, it's not just random noise, but rather each call has a meaning.
One call will fill the monkeys with fear and make them look anxiously at their feet. It's a fair guess that this call is a warning, something like, "Hey! A snake!" A different call makes them run for high grass and look up at the sky, "Hey! An eagle!"
Since Martial eagles and black mamba snakes are predators of Vervet monkeys, it's a good guess. That may not be language in the sense that humans use the term, but it is intelligent vocalization.