My Big Question

My big question is have you ever said a word repetitively to the point to where it sounds like the weirdest word in the world. I mean try it with me Engine engine engune engan engien . You repeat it so much it's almost impossible to pronounce it right the next time. I guess what I'm getting at is how did these names come upon us how did these words create our English vocabulary. Who spoke our language the first time ? What If it used to be all written and nobody spoke and then one day someone tried to say it and mispronounced it and now we say cow instead of couw. I guess we will never know but that is my BIG QUESTION.