We need to make English the official language of the United States. There are several reasons, but first and foremost is national cohesion. Having English as an official language would help unify our diverse population by providing a common means of communication. Immigrants would be integrated into a broader society. The last sentence is personal to me.
My great-grandmother lived in this country for decades and never spoke English. She missed so much, confined to her home with only family who could converse with her. She was a second mother to me for the first three-plus years of my life. I learned some of it when I was young, but as I got older, my communication with her was a smile and a nod in response to what she said to me. Sad for both of us.