Is it that time again all ready? Yes, because having only word origins is kind of boring. We need to know what the letters are about. And our friend F has an interesting story. For one thing, it’s more related to the letter W than it is to the visually similar E!
First of all, look back at the alphabet .gif. F has two equivalent letters: phi (Φφ), where it gets its sound and the secondary letter digamma (Ϝϝ), where it gets its appearance. Digamma (so called because it resembles a double Gamma Γ) may be unfamiliar to you, but it is indeed a Greek letter, albeit one that fell into disuse sometime around the seventh century before the Common Era/Anno Domini. Yes, it was disregarded that long ago, and its influence is still present.
The reason digamma was not forgotten is that the Romans had a peculiar habit when they spelled things: they differentiated the words they took from outside origins. The reason the word chaos is pronounced with a k sound is because English took it from the Roman spelling, which was taken from the Greek khaos. Similarly, the Romans took digamma, flipped it around and used it for their “f” sounds, except when that word was Greek in origin. Then it kept the phi-influenced ph spelling, as in phobia.
That makes F one of the newer letters on the block, made by the amalgamation of a letter that sounded like “waw” with a sound like phi. The old waw pronunciation of digamma also gave way to u, v, and w, although those three symbols came from a different origin. In linguistic terms, F is called a labio-dental surd (lip-teeth voiceless, because it’s a breath-sound made with your upper teeth on your lower lip).
And right now, you're all making the "ffff" sound to see if that's true.
The History of the Alphabet .gif
The Facebook page on waw/wau (Yes, there is such a thing).
Dictionary.com (because no matter how many times I do this, I forget what surd means).