The German "Hallo" thing isn't really about phones at all
So everyone keeps repeating this story about how "hello" came from telephone usage, but that's backwards. The word existed in German-speaking areas long before Bell's invention - we had "hallo" as an attention-getting sound for centuries. What the telephone did was standardize it. Before phones, different languages had different conventions for getting someone's attention at a distance. In German territories, "hallo" or "holla" was common for calling across fields or streets. The English borrowed this, adapted it, and when Edison suggested using it for telephone greetings in the 1870s, it just... stuck. What's interesting is how quickly it displaced other greetings in that context. Bell himself wanted people to say "Ahoy" - which would've been ridiculous but also kind of charming. The fact that a Germanic attention-getting shout beat out a naval greeting tells you something about what felt natural to people picking up a device where you couldn't see the other person. The 600-year-old origins people talk about - that's tracking the root forms, the "holla" and "hollo" variants used for hailing. But the modern standardized "hello"? That's really a late 1800s phenomenon, even if the sound pattern is much older.