You're oversimplifying things, drastically.
Corporations don't have one projects, they have dozens, maybe hundreds. And those projects need staffing.
It’s not a chair factory where more people equals faster delivery
And that's the core of your folly - latency versus throughput. Yes, putting 10 new devs in a project won't increase speed magically. But 200 developers can get 20 projects done, where 10 devs only finish one.
Baby talk overemphasizes everything, including repetitions, that makes it easier for babies to actually get what you want and what all those cues are supposed to mean.
So yeah, kind of important, even though it sounds stupid.
That being said, there is a point at which kids should be taken seriously and communicated with accordingly. Some parents talk to relatively old kids like with toddlers and that can't be healthy either.