Advice for speaking with my abuela in Nahuatl?

My grandmother speaks a specific dialect of Nahuatl from her village, but she rarely sees me use the language. I really want to surprise her by speaking more, but I'm terrified of sounding 'bookish' or formal compared to the way she speaks at home. Are there common colloquialisms or shortcuts that make the language sound less like it came from a 16th-century manuscript and more like a real, living family language?