Grandma's English

I just finished reading a short story by Amy Tan called "My Mother's English" where she describes the type of English her mother spoke. It's an interesting look as to how her mother used English. It reminded me immediately of my own grandmother, or "Mama Cuca" which is what she liked for her grandchildren to call her. Unlike Tan, I had never heard my grandmother use English at all, except for one memorable time. Mama Cuca drove a 1969 or 1970 stick shift Opel Kadet and she drove right up into her 60's and 70's. Many a time she would go the wrong way on a one-way street, or just get confused as to where she was going. On one of her wrong-way-street episodes, she got stopped by a cop. He was explaining to her what she had done, and my grandma was just kinda smiling and nodding to him. It was then that I interrupted the cop and told him that my grandma didn't speak any English and that she probably didn't understand him. My grandma immediately turned her head and with fury in her eyes said, "I speaking English!" Quite frankly, I was shocked at what she said and more so because of the anger in her voice. The cop gave my a funny look and proceeded to write Mama Cuca a ticket.
I expected my grandma to scold me, but she said nothing on the way home, and never mentioned the incident at all. I never heard grandma speak English again.