Okay, so imagine that Dumbledore eventually gets Wi-Fi installed at Hogwarts. Most of the students don't realize it because they don't know what Internet is.
But during the speech at the beginning of the year, he asks if there's any questions. A first-year muggleborn rasies their hand, whips out a smartphone, and asks for the Wi-Fi password. Dumbledore says "lemon drops" without pausing and the purebloods are left thinking that Wi-Fi is some secret club or something