My mother can't say I don't have respect for her when she doesn't let me talk when I want to say something in return as a normal discussion and she doesn't show me respect. How wrong am I here?

Everyone should have the right to speak their mind if they do so in a respectful way. Even if people disagree they should be able to be heard.

Let her finish what she wants to say and tell her what you feel. If it doesn’t work then try writing a letter or a note to your mother. You just want to communicate with her and she also is trying to communicate with you. Both of you have same target. Work on priority basis for speaking with each other. And if any confusion is there, just decide and act..... May be in such situation you just leave for the right time, and when she is receptive tell her nicely what you wanted to share with your mother. So wait for right time, Convey your thoughts and feelings, If this doesn’t work try to communicate with other means or resources of communication.