When Lions roar, or Dogs show aggression, they do that snort-roar thing. They're producing sound while inhaling. How did that come to be when all (?) other forms of sound involve exhaling?
Humans do produce sound while snoring, but that's merely a by-product of it.
And while people could very well speak by inhaling, they don't do that in their regular communication. Lions and Dogs do. Why/when did they decide that (inhaling sound production) was a better/more effective means of making sound?