After a Let’s Read about At The Mountains of Madness, and remembering how Shoggoths weren’t even meant to have PERMANENT brains but only grow them when the command given...
I’m starting to wonder if the Shoggoths weren’t as intelligent as thought, or didn’t gain any consistent intelligence until started hanging out with sorcerer types and cults.
But then again I think its more likely the Elder Things were in denial of the shoggoths intelligence given the smearing of a message on the walls after finding ones.
But it might have been a mix of both. The attempts to further constrain the Shoggoths and prevent a slave uprising (or another if the earlier time of rampages in times of dinosaurs was an uprising and not a sort of glitch or bug as the Elder Things insist ) instead caused a HAL style breakdown. The Shoggoths might have lashed out in rage while still instinctually talking in pre-recorded phrases similar to what phone A.I’s use.
Its also possible the Shoggoths got around issues by immitating the vocal commands for override codes for eachother. A shoggoth might not have been able to kill on their own, but if another shoggoth gave the order while imitating the shape of their masters...
Instead of being a parallel to human slavery, its an attempt to stunt the growth of the shoggoths.
I don’t doubt the possibility of intelligent shoggoths, but its possibly they did not developed any coherent, sane intelligence until after throwing off their chains and even then after leaving the toxic influence of the strange unknown horror upriver the Mountains of Madness.
Or the shoggoths might have a very alien intelligence even in modern times, perhaps even turning off higher cognition in times when food is scarce.
Going farther into speculation:
It should also be noted that I wouldn’t be surprised if the earlier control methods of Shoggoths wasn’t hypnosis as humans thought but a telepathic interface. If so the nature of the uprising could have been very different from the later voice controlled version: with instead due to the Old Ones unknowingly leaving bits of copies of their minds in Shoggoths each time made use of one, until it congealed into something that might be horrified and not even know what it is and panicking at its sudden sense of self and struggling with contradicting memories.