Hello Анна,
parler = to speak, to talk
dire = to say, to tell
A few examples:
Je sais parler le français. I can speak French.
De quoi parles-tu? What are you talking about?
Je ne comprends pas ce qu'il dit. I don't understand what he says.
Elle m'a dit de partir. She told me to leave.
Hope this helps!
Micha.