As everyone who has heard the song can attest, English has 26 letters. But what few people know is that it used to have far more characters. The following video explains ten of the characters that have been dropped form English, including for example thorn, the ampersand, and the "long s".
Everyone knows the ampersand, and you also know the thorn - you just didn't know its name. Thorn was a symbol representing the Th sound, and was frequently displayed as a "Y", so all those businesses called "Ye Olde This or That" actually have a name that should be pronounced as "the old this or that".
And then there is the "long s". If you have read old documents (such as the Declaration of Independence) you may have noticed that some words appeared to use an "f" in place of an "s". Congrefs was one example, only that wasn't an "f" in the original document - that was a long s.
This is a fun video, but it's not completely correct - at least one of these letters is still in use even though it has been dropped from virtually all keyboards and font sets.
Speaking of videos, do you know what would also make a good video? A list of letters that were late additions to English.
The letter "j", for example, was still not commonly used as late as 1800. It had only been added to English a couple hundred years before, and many words spelt with a J could also be correctly spelt with an I.
This is part of the reason why Washington DC has no J Street, and why I and J are placed next to each other in the alphabet.