Maybe I'm over thinking this, but it seems like there would be a massive language barrier between the conquistadors and the locals to overcome, especially in so short a time frame.
Cortez went through two translators in order to translate what he wanted. Gerónimo de Aguilar was one of two Spaniards shipwrecked in the Yucatan from an earlier expedition. The other became a war chief and helped the Maya resist Spanish forcers. Aguilar, during his time of captivity, learned the local language. When Cortes happened upon them he took Aguilar with him as a translator. The other translator Cortes had was Malinche who was a Nahuatl speaker sold into slavery to the Yucatan area. She learned the same dialect as Aguilar. Through these two Cortes was able to communicate with Nahuatl speakers from central Mexico.
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