Grandparents only speak Japanese

When I was a child, every grandma and grandpa or older person my sisters and I  knew, only spoke Japanese.  We all thought that when you became a grandparent you would automatically only be able to speak Japanese.  We worried that we would not be able to communicate with our grandchildren.  I remember one day we were sitting at the kitchen table and we expressed our concern to our mom.  My mom was stunned that we all thought this.  She calmly explained to us that since we spoke English now, we would when we were older and she assured us we would be able to speak English to our grandchildren.  We were all relieved to hear that from our mom.