My 25 year old daughter stopped talking to me ...

if its not possible to speak write her a full letter asking why-say that if you have upset her you need to know in order to deal with it.Tell her how important she is to you and that its so sad not to be speaking.If she doesnt respond just try again later

I agree with minnie.  I know it must be hard for you not talking to your daughter.  Do you have any idea why she stopped talking to you?  Maybe you could try apologizing and leave the door open for communication, I am sure she will talk to you when she is ready.

Hi,
It is obviouse that she is trying to say something by that..... I bet that she is: angry / upset / disappointes / feels discriminated .....  etc, etc.....
Most probablly you know the exact reason..... If you do, you also know what actions you should take..... if you don't than you MUST find out (approach her or send someone).  She is 25 years old, she is a matured adult and sure has a reason for that (assuming she is normal).  I believe that the ball is in your court..... better go an extra mile towards her.... please give up your ego.... you are the father and it's your leadership that is in great need now....  The worst thing you can do is sit aside and do nothing.... you MUST be proactive and show her you do care and do mind and do all you can (time after time) to improve the relations with her..... even if you think she is absolutely wrong.....
Best regards,

Well first of all what caused her to quit talking to you?

In order to answer the question it appears as though this issue is part of some long standing unresolved issues you and she have not taken time to try and resolve, you won't be able resume communications until that matter is corrected. It may require the help of a Family Counselor.