What Language Should My Grandson Start Learning to Read?

Using the card system, you could do a set of cards in English where they're learning everything in English. And then if they speak Spanish, if one of them speaks Spanish, I'm guessing one of them speaking Spanish,. Maybe both speak Spanish, they could at different times of the day also do Spanish. They would get three languages. Do all three. This is a good good opportunity. What language should my grandson start learning to read? All of them.