Siri suddenly doesn't recognize most of my contacts

Question

Over the last few weeks, I have been unable to get Siri to recognize even the most simple of names in my address book. It is quite infuriating. These are names like Cory or Jessica. It instead finds some similar word in the dictionary and says I have nothing in my address book that matches and would I like to search for businesses with that word.
I tried turning Siri off and then back on, thinking it might reset something on apple's end, but same result.
It seems to be fine for contacts I've taught Siri are related to me like "call my brother." But virtually every other contact name isn't working. Any ideas?

Answer 1

Siri does this to me, too. E.g., I call Nena Smith several times a week.  One day, it said "sorry, there is no Nena Smith in your contact list" which was ridiculout.   After several requests (and blood pressure going through the roof of my car) I was able to turn off the phone and then turn it back on.  After the reboot, Siri again recognized that Nena was in my contact book by the time I pulled up to her house.
Funnily enough, today I called Nena again.  I say "Call Nena Smith" and Siri says "do you want to call Laura Smith?" and I say NO! and Siri says "whom do you wish to call?" and I say Nena Smith, and Siri says, "do you want to call Laura Smith . . . and we're off.  It refuses to call Nena Smith and will only call Laura (a person I seldom call).  I rebooted, but that didn't solve it.
Another one:  Call Ann Roberts.
There is no Ann Roberts in your contact list.  Would you like to call Robert Jones or Ann Roberts?
Even if I say Ann Robertssssssss it refuses to call her!
What is wrong with Siri?  These are only two of many examples.
And more important, even with humans with a problem, the important question is
How do I fix this?
Thanks.