why won't siri try to learn and why is it inconsistent in recognizing names

I want to know how to train siri to learn to recognize what I am asking for.

I am often running into the situation where I ask siri to call someone in my contacts and it will repeat the name back to me perfectly, but say that it cannot find the name in my contacts.

Also, sometimes it will simply call a name that looks or sounds similar but is not the name in my contacts I asked for.

For example, if I ask for Corinne it will only give me Karen, even though Corinne is in my contacts. And there is no option I am aware of to ask siri to learn Corinne. (by the way it is pronounced differently to Karen)

Then for years I was able to say "Call Mom" and siri would call my mother's number. But then siri started to ask "What is your mother's name"?????

The last situation is where I ask for a name that is a bit different and siri says the name is not in my contacts, ... when it is. The crazy part is that siri repeats the name back to me just as I said it. And there was once, and only once, that siri actually asked me to spell the name I was saying. But then it still did not matter.

Help