Å, ä, and ö are three special characters used in the Swedish alphabet. They are known as "diacritical" or "diacritic" letters and are distinct from the standard English alphabet.
Å (å): This letter is pronounced as a long "o" sound in English. It represents a unique vowel sound in Swedish. For instance, the word "båt" (boat) uses the letter "å."
Ä (ä): Pronounced as the short "e" sound in English, the letter "ä" represents a specific vowel sound in Swedish. For example, the word "sätta" (to put) contains the letter "ä."
Ö (ö): This letter is pronounced similarly to the "u" in the English word "fur." It represents another specific vowel sound in Swedish. For instance, the word "köpa" (to buy) contains the letter "ö."
These letters are integral to Swedish and are used extensively in writing. They contribute to the unique sounds and pronunciation found in Swedish words. In addition to Swedish, these characters are also used in other languages, such as Finnish and Norwegian, although their pronunciation might differ.
Linnea, OLS Community Manager – Swedish

Source: Linnea, OLS Community Manager