The German alphabet has a special letter "ß"; approximately how is it pronounced in English?

In the German language there are four special letters in addition to the regular 26-letter alphabet. Three of these special letters, ä, ö, ü, are also used in other languages. The fourth, the letter ß, is only used in German. Its pronunciation is approximated by the “ess” sound when reciting the alphabet in English: in other words, it sounds like the “s” in “post”, but not as in “posed”. It does not sound like the letter “z” either in English or in German.

The letter ß, has two names. It is sometimes known as “scharfes S” ("sharp S") which captures its pronunciation. Alternatively. it is known as “Eszett” which captures the origin of the written character. Although ß looks like a “beta” (the Greek B) it was originally formed from a long “s” (written “ʃ” and named “Es” in German) combined with a “z” (named “Zett” in German).

In the 20th century, "ß" was completely replaced by "ss" in Swiss Standard German (used in Switzerland and Liechtenstein), while it remains part of the orthography of Standard German elsewhere.

It is useful for the non-German-speaking traveller to know about ß. If you wander around a German town, you will see lots of signs containing the word “Straße” which simply means “street”. In Switzerland things would be a little easier because the word would appear as “Strasse”.