I and my family have noticed Siri has gotten hard of hearing and less intelligent, too. I really am at a loss to figure it out. I've run tests on my iPhone 7, and Google Assistant on Allo gets my speech very accurately, so I have figured out that it's not a mic issue, as Apple execs had tried to imply several months ago. Nor a processor issue, I would guess.
Siri seems slower to react and slower to return answers and she doesn't seem to understand me very well anymore. I keep reading how Apple has all these teams working on Siri and places great importance on Siri so why is she getting noticeably worse, especially at parsing speech?
I have always been a big fan of Siri and defended my experience of her abilities on this board. Now the fact is that Siri is as difficult for me to use as she has been for the men and some women outside of the US, who have been having problems with Siri for ages. I always thought men in particular were having trouble with her because their deeper voices could be picked up as mumbling. Goodness knows I have that problem making sense of my husband's speech, myself.
Throw in a thick regional accent into the mix and I can understand the challenges. But I have a medium to high pitched tone and had a career speaking to the public, where it was essential that I developed the habit of enunciating clearly and making myself easily understood. I should not be having the problems with Siri that I've been having.
Sorry for derailing the thread a little but AI is an important feature to me. I'm eagerly waiting to see who will have the best implementation of it for 2017. I still am in shock that Samsung acquired most of the team who created Siri.