Do you find it jarring to see the word “hello” in Regency era (or earlier) novels, or do you not notice?

“Hello” did not exist in the Georgian era, much less in England.

It began in America post-Regency, but not as a greeting. In the 1830s, in America, it was used as an expression of surprise, becoming popular in the 1850s as a way to attract attention or announce one’s arrival—still in America, mind. Not until the 1880s did it shift to become a greeting (but still not crossing the pond).

When the telephone was invented, it was important to standardise a proper greeting. Thomas Edison and Alexander Graham Bell were at odds as to what that greeting should be. Bell proposed “ahoy” since it has been used as a nautical greeting for centuries. Edison liked the idea of a greeting that captured the idea of “hail,” “hale,” and “hallo,” and so he proposed that newly popularised exclamation of surprise: hello. In the end, Edison won.

The first telephone book was published on the cusp of the 20th century with a How To section. “Hello” was explained in that section as the official telephone greeting. The word now crosses the pond into England at the turn of the century as a telephone greeting.