My grandparents, all 6 of them, came to this country from Italy shortly after the turn of the last century. While my maternal grandmother and my paternal grandfather learned English well enough to make themselves understood, my paternal grandmother and maternal grandfather hardly spoke English at all. My father spoke Italian at home growing up and only started speaking English when he went to school. He spoke Italian to his parents all their lives.
My stepmother also grew up speaking Italian to her parents. You would think with all the Italian speakers in my family, we grandchildren would have learned to speak it, too, but none of us did. I know a few words, but not enough to communicate with my grandparents. Bilingualism was suspect back in the day. My parents wanted their children to be Americans first and foremost. We had American names, not exotic Italian ones like "Savario" and "Francisco" (my Uncle Sam and my Dad). When Uncle Sam's daughter wanted to give her son "Savario" for a middle name, he talked her out of it. My grandfather called my Dad "Franci" (pronounced like "Frangi"), but everyone else called him Frank.
Naturally it has been the big regret of my life that I wasn't named "Francesca". An even bigger regret is that I never learned Italian. My parents spoke it often enough with each other and their parents that a more enterprising child should have been able to learn something, at least enough to communicate with her grandparents. As it was, they remained puzzling strangers to me. As my grandfather grew older, he forgot a lot of his English, which made it even harder to talk to him. We spent the last year of his life playing the card games he taught me. Although he was a demanding man who, as my sister put it, had a lot of religion but no spirituality, my memories of playing cards with him are precious to me.
So when I became a speech pathologist and worked with children whose grandparents spoke another language, I did what was contrary to my early training, and encouraged parents to teach their children both that language and English. It was sometimes a hard call. One of my little clients was a stutterer who stuttered more when his grandparents came to visit and the family switched to Spanish for a few weeks. But the other option, him not having a real relationship with his grandparents, seemed a whole lot worse.
Of course, educational opinions change, and now bilingualism is encouraged rather than frowned on. I think the best solution was hit on by friends of ours. They spoke only Chinese with their children until the children reached three or so. As J told me of her younger daughter, "I know she is going to learn English." And of course she will. She lives in an English speaking country. Her friends speak English. The television programs she watches are in English. The neighbors speak English. But her grandmother, who cares for her every day, speaks only Chinese, and they will always be able to speak together.
My Dad actually forgot his Italian as he got older. Once his parents were dead and we kids were out of the house, so that he and Mom did not need a secret code to use to say, "Where did you hide the Christmas presents?" he stopped speaking it altogether. When my son took a few semesters of Italian in college, he wasn't able to practice with Grandpa. Go figure.