parents tend to yell at the same time and it needs simultaneous processing

Your example is needlessly bleak, but in general: yes, we're a social species and being able to process multiple speech streams seems obviously pretty important in many social contexts involving more than two people.

Seems doubtful to me that there will be any hardware in our species specific to processing language. It's going to be the same basic hardware as Chimps. Whatever is going on that's related to us being a social species is all software.

Uh, there definitely is "hardware specific to processing language" for our species, they even have their own wiki pages[0][1].

And in general our brains differ significantly from that of a chimpansee. Human brains push neuron density to to absolute limit within the animal kingdom and have unique evolutionary adaptations that allow for it. As a result our species also has mental health disorders unique to us that seem to be cause by the neurons being pushed past that limit.

[0] https://en.wikipedia.org/wiki/Wernicke%27s_area

[1] https://en.wikipedia.org/wiki/Broca%27s_area

Also explains why we like music with two simultaneous distinct sections (bass + the rest). One without the other doesn't feel as complete

This is a completely different phenomenon. Your ear/brain are tuned to rhythmic beats in the lower frequencies (footsteps). We're better at pattern recognition with the lower frequencies.

Also, our brains will encode the differences in registers to evoke emotion differently, which is often used by horror films to make a scene scarier[0]. Evolutionarily this is probably to detect screams or babies crying, a rustling bush, etc.

Speech encoding, at least per this article, has little to do with that. We don't have music encoding so much as we have pattern recognition, instinctual emotional respond to sound, etc.

Another great video about how music is perceived in animals is [1], just while we're on the topic.

[0] https://www.atlasobscura.com/articles/how-the-hidden-sounds-...

[1] https://youtu.be/0ZYhyewNQMo?is=0mWSRAzObOD2p32E