Having lived in the United States for all of my life, English is my native tongue. Some languages, like German, have similar letters and alphabets. I knew what umlauts were when I first started learning German, but one day I came across the giant weird capital B and I had no idea what it was. I still don't have any clue to what this B is. What exactly is it called? And why does it make a "sss" sound?
"Eszett" (or "scharfes s" = "sharp s") is called that because it was originally formed from s+z (the old, long s that looked a bit like an f, and the z with the extra bow on the lower end). It still turns up as two separate letters in some old books (pre-1900), most notably the Brothers Grimm's dictionary (which was continued after their deaths in the original style). But since the late 19th century, "ss" is always used instead of "sz" when there is no ß available (also when whole words are in capital letters, as, until a few years ago, there was no capitalized ß, and the one that exits = ẞ didn't really catch on). Switzerland and Liechtenstein got rid of the letter completely quite a while ago and now always use ss.
In German as spoken in Germany though, ß is preceeded by long vowels and ss by short vowels (find pronunciations of the words online if you want, but it may take a time to hear the difference):
Die Tasse (cup), dass (that), das Schloss (castle, lock), der Kuss (kiss)
vs. schließen (to close), das Maß (the measurement), groß (tall), der Gruß (greeting).
Wow! Thanks for this huge answer! Even though I knew what the ß is, it's always good to learn even more! Here's a lingot!
Hello Maya! Living in Switzerland I also sometimes have trouble with "ss" or "ß". You can find the correct letter in the dictionary www.dict.cc + German/English. And on your Keyboard it is found under the ASCII-Table with the button-combination "Alt + 0/ins + 223". Push "NumLock" before! You will also find it under WinWord/Insert/Symbols.