"My sister doesn't listen when I speak to her." should be accepted. "To me" is redundant in the English translation of that sentence. Who else could it be?
Parler can mean "to speak" or "to talk". Either verb should be acceptable in the answer.
Either verb is accepted in translation. So, your mistake was somewhere else in your sentence.
how can I get a typo when I used only the prompts given by Duo ?!