Do you think animals understand emphasis?

I catch myself repeating my dogs’ names on occasion, when they are not listening. Humans would recognize my different tone of voice as urgent, and often getting annoyed, too.

I’m wondering whether there is anything similar in the animal world – a signal that is repeated in a slightly different manner, because there is an added message.

Most notably, I heard a guy whistling for his dog last week. His whistle consisted of two short notes at first, similar to the “ding-dong” of a doorbell. When the dog didn’t respond, the whistle turned into something entirely different: Both notes longer, more pronounced. When you’re battling with a language that is not your own, these things must be confusing.