The Letter "O" in German In Standard German

The sound of "o" changes based on the letters around it, whether it carries the word stress, and whether the word is originally German or borrowed.

Say "o" long when it is at the end of a word, when the word changes to add a vowel in other forms, or before the letters "ß". This sound is round and clear.

Say "o" short and open when it is followed by two or more consonants that stay together in all forms of the word. Double consonants are a clear sign.

In weak positions - before the main stress, before another vowel, or at the end of loanwords - "o" becomes a light, quick /o/.

In French loanwords, when "o" comes before an "n" or "m", it often gets a nasal sound through the nose.

"O" combines with other letters to form fixed sounds in German.

Two "o"s together always mark the long /oː/ sound

An "o" with an "h" after it also guarantees a long /oː/, no matter what follows.

The group "oi" is rare. In some loanwords and southern names, it sounds like the "oy" in "boy".