Nahuatl is a language spoken by indigenous peoples in Mexico, including the Aztecs. It is still spoken today by some communities. Nahuatl has had a significant impact on Mexican Culture and its vocabulary has influenced Spanish and English.
Marina was born a lady but her mother sold her into slavery so that the son would inherit everything. She had a gift for languages after living with the indios she had been sold to as well as the Aztec Nuhuatl. Cortez needed an interpreter and there she was! His real wife remained in Spain and he took her as his mistress and she became called Dona Marina and bore him one son, Don Martin. After being sold into slavery, what a perfect revenge. But, as things go, Cortez eventually didn't need her any more and abandoned her. As for his son, mixed blooded children were treated worse than either pure Spanish or pure indio.