[nitwit005]

We don't know what operations the brain is actually doing, so declaring that it is performing them efficiently is pure speculation.

Similarly, the brain surely has limits to parallelism, for the same sorts of reasons a computer does. You only have one mouth, so if two parts of the brain tried to speak, fully parallelized, you'd get nonsense at best. They have to agree on what to say, which is effectively serialization.

[antris]

The mouth as an example with regarding to speech doesn't work very well. People can say one thing, but say it in a way that means the complete opposite. So already we have tone incorporated into our speech. Who knows what kind of subconscious thoughts we embed into our speech that are not yet understood well.

Then there's the combination of tone and the words, accent, body language and every other context embed into our language that produces a very complex meaning, even for one word.

[nitwit005]

It doesn't matter what was factored into the speech, you still can't speak in parallel. It's not physically possible. At some point you need to get agreement as to what the output should be.