I like to collect the stories of different words that I hear.
Old English
Many of the words of the English language come from Old English. But you knew this already, because you're very smart.
Old English is not just any variety of English that is old. Saying "thee" and "thou" as if you were reciting Shakespeare or reading a Bible verse puts you in the Early Modern English period, so not Old at all. Saying "Ye Olde" is at best Middle English. To reach the period of Old English you have to go sufficiently far back in time so that the meaning of the words is hardly recognizable.
Old English had seven vowels: a, æ, e, i, o, u, y. Each of these could have a long or short duration, which was not really represented in the writing of the time. To tell vowel duration apart in modern transcriptions, you can put a straight line over the vowel to show long duration: ā, ǣ, ē, ī, ō, ū, ȳ.
Some words from back them are still written mostly the same. The old "wē" is still "we", and the old "in" is still "in". The pronunciation however is a different story.