Language, Language...Please!

Have you ever wondered at the origin of words? I'm not talking about if it's rooted in Latin or Greek or whatever, but the actual ORIGIN. Take for example the word 'Hello'. I suppose you could say it's a universal greeting, but where did it come from? Did a random person one day try and mumble something to a mate and out popped our now accepted form of speech? Or was there perhaps a panel of Language Judges who considered many options and eventually voted for our winner?
Who knows, maybe it was a toss up between hello and... hmmm... let's see, maybe even Goodbye. So a man walks into a bar and says: "Goodbye, give me a brandy on the rocks."

Who was it who decided that 'a' would be the first letter of the alphabet, or, for that matter, that we would have 26 letters to create a whole language? On that matter, how do we know what 'a' should sound like, maybe what we know as 'a' should actually sound like 'e', or 'l'.

Hmmm... food for thought anyway.