As stated above, there were several letters in Middle and Old English which no longer appear in Modern English, but which are still interesting none the less, and still come up once in a while, particularly for medievalists.
  • Æ æ: "ash" pronounced like "a" in hat
  • Þ þ: "thorn" pronounced like "th" in thread; it is derived from the Germanic Runes or "Futhark." Interestingly enough, the form of this letter gave us that quaint word "ye" as in "Ye Olde Shoppe"--The loop of the Þ gradually seperated from the top end, forming what looked like a y, and thus leading to the written form "ye"--however, both forms--"ye" and "the" were used, until "the" eventually became the standard as education became uniformed in the late nineteenth century.
  • Ð ð: "Þæt" in English, but currently known by its Icelandic name "eth"; it is pronounced like "th" in leather
  • P p: "wynn" meaning "joy"; pronounced like "w"; this letter is not supported by HTML, and so I have given an aproximation found in the shape of the letter P, which looks almost identical. It is also derived from the Runes/Futhark, and is generally rendered "w" in most texts.
  • 3 3: "yogh" whose pronounciation is complicated, but is usually rendered "g" or "y"; it is not represented by HTML, but looks like the number 3, which I have substituted here.

BrianShader says "re Middle English : If I remember rightly, the original form of the "thorn" letter remained alongside the 'y' form until the printing press came over from Germany. These presses had no thorn symbol and so y was used instead, and thus the original form was completely erased."

Me says Interesting point.

To which Txikwa offers this rebuttle: "re Middle English: There were manuscripts in the 1300s where Y was used for thorn, i.e. where they'd become identical in shape, so it wasn't just a matter of printing."

Me says Ahh. Getting more interesting.