We use hello several times a day to greet people or attract attention. But as prevalent as the word is, it is relatively new.
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WHERE DOES HELLO COME FROM?
While use of the term hello dates back earlier, it isn’t recorded with this exact spelling until the 1800s. Hello is considered a variant on a number of other similar words—like hallo, holla, and hollo—that were used to hail and shout to gain attention and recorded prior to the 1800s.
For example, the word hallo demanded that the listener come to a stop or cease what he or she was doing. It was also used to spur on hunting dogs.
Amazingly, there are countless variations of these words, including: halloo, halloa, halow, hillo, holler, hollo, holloa, hollow, and hullo. Some of these may sound more familiar than others.
Hello as used as an everyday greeting is recorded since at least the 1850s. Because it’s such a common word, we might have expected that greeting to be recorded earlier. This spelling is considered an Americanism, while hullo is a variant that is more commonly seen in Great Britain.
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WHY DO WE ANSWER THE PHONE WITH HELLO?
When the telephone was invented, Alexander Graham Bell wanted people to use the word ahoy as a greeting. Supposedly his rival Thomas Edison suggested hello, while Bell stubbornly clung to ahoy, and well—you know which one stuck around. (Interesting trivia: hello-girls was the name for the central telephone exchange operators.)
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WHAT ABOUT OTHER GREETINGS?
Hi is equivalent to hello, but it is considered a little bit more informal in tone. In fact, it was recorded a lot earlier than hello. Hi developed from the Middle English hy, similar to hey and ha.
As for the upbeat greeting howdy, it was first recorded as a contraction of “how do you do” in 1632. An earlier version comes from “how do ye.”
From Dictionary.com