Language is often quite literally at the center of “MexicanAmerican,” with director Eddie Sánchez placing subtitles in the middle of the screen as his parents will tell the story of their family in Spanish, their primary tongue, while the translation to English isn’t always only for the benefit for audiences abroad, but for the filmmaker himself when he was raised across the border from them, perhaps geographically within a few hundred miles but by all other measures a world away.