I think that a book titled "WE" by John G.H. Dickinson
is what you are looking for.
My memory of the book is a bit fuzzy as IIt covers the following elements of your answer:
- The World Ear system (the titular "WE") allows humans to achieve near-telepathic communication experience
- The engineer chosen to travel to Pluto is called Paul Munro
- I'm not sure if the implant was removed for the journey, or simply because the rigours of living on such a remote colony/outpost wouldn't allow people the luxury of staying attached to the World Ear
- He does have problems acclimatising after the removal, which might have included speech problems.
- The problem he (and the team of the outpost) discover is that the World Ear system unwittingly linked humanity into one giant hive mind/super-organism, with individual humans losing their distinct identity within the overarching system of the World Ear. This is quite close to what you refer to as the "AI being broken"
- I don't quite remember whether the AI is trying to kill everyone. What happens is that the one of the female colonists gets successfully pregnant(?), and the rest of the colonists are trying to keep that a secret. The secret gets out, because the station is damaged to the extent that they require assistance from Earth. The colonists hypothesise that the World Ear will now figure out that it's possible to establish sustainable colonies outside of planet Earth, and spread outwards. The problem with that is that it's no longer humanity colonising the stars, it's the World Ear that happens to inhabit human hosts.
I don't have access to the text of the book right now, so I'm unable to provide quotations yet.