i have a headcanon that after the second wizarding war, muggle technology got sort of integrated into hogwarts to allow closer communication with muggle friends and family
so they have like phones and stuff to use to call home
little daisy dursley calls home on her first day of school
Daisy: “Daddy, I made it into Ravenclaw!”
Dudley: “Oh, Ravenclaw, the, um–” [covers receiver and turns to Harry] “What the hell does that mean?”
Harry: “Smart house.”
Dudley: [goes back to Daisy] “THE SMART HOUSE! Oh, I am so proud of you!”