Distinct letter

The character Å (å) is derived from an A with a ring. It is a distinct letter in the Danish, Norwegian, Swedish, Finnish, Walloon, and Chamorro alphabets. For example, the 29-letter Swedish alphabet begins with the basic 26 Latin letters and ends with the three letters Å, Ä, and Ö.

Overring

The character Ů (ů), a Latin U with overring, or kroužek, is a grapheme in Czech preserved for historic reasons, and represented a vowel shift. For example, the word for "horse" used to be written kóň, which evolved, along with pronunciation, into kuoň. Ultimately, the vowel [o] disappeared completely, and the uo evolved into ů, modern form kůň. The letter ů now has the same pronunciation as the letter ú (long [uː]), but changes to a short o when a word is morphed (e.g. nom. kůň → gen. koně, nom. dům → gen. domu), thus showing the historical evolution of the language. Ů can occur in only the medial position, and ú occurs almost exclusively in initial position or at the beginning of a word root in a compound. The characters are used also in Steuer's Silesian alphabet. The [uo] pronunciation has prevailed in some Moravian dialects, as well as in Slovak, which uses the letter ô instead of ů.

The ring is used in some dialects of Emilian and Romagnol to distinguish the sound /ʌ/ (å) from /a/ (a).

ů was used in Old Lithuanian in Lithuania Minor from the 16th till the beginning of the 20th century and for a shorter time in 16th-century Lithuania Major for diphthong [uo].

The ring was used in the Lithuanian Cyrillic alphabet promoted by Russian authorities in the last quarter of the 19th century with the letter У̊ / у̊ used to represent the /wɔ/ diphthong (now written uo in Lithuanian orthography).

ẘ and ẙ are used in the ISO 233 romanization of the Arabic alphabet. A fatḥah followed by the letter ⟨ﻭ⟩ (wāw) with a sukūn (ـَوْ) is romanized as aẘ. A fatḥah followed by the letter ⟨ﻱ⟩ (yā’) with a sukūn over it (ـَيْ) is romanized as aẙ.

Ring upon e (e̊) is used by certain dialectologists of Walloon (especially Jean-Jacques Gaziaux) to note the /ə/ vowel, which typically replaces /i/ and /y/ in the Brabant Province's central Walloon dialects. The difficulty of typewriting it has led some writers to prefer ë for the same sound.

Underring

The underring is used in IPA to indicate voicelessness and in Indo-European studies or in Sanskrit transliteration (IAST) to indicate syllabicity of sonorants.

Half rings

Half rings also exist as diacritic marks: the characters U+0351 ◌͑ COMBINING LEFT HALF RING ABOVE and U+0357 ◌͗ COMBINING RIGHT HALF RING ABOVE. These characters are used in the Uralic Phonetic Alphabet, respectively for mediopalatal pronunciation and strong-onset vowels. The characters may be used in the International Phonetic Alphabet to denote less and more roundedness, respectively, as alternatives to half rings below U+031C ◌̜ COMBINING LEFT HALF RING BELOW and U+0339 ◌̹ COMBINING RIGHT HALF RING BELOW. They are here given with the lowercase a: a͑ and a͗, a̜ and a̹.

U+1E9A ẚ LATIN SMALL LETTER A WITH RIGHT HALF RING is similar in appearance but differs from a͗ because its compatibility decomposition uses U+02BE ʾ MODIFIER LETTER RIGHT HALF RING instead of U+0357 ◌͗ COMBINING RIGHT HALF RING ABOVE.

Other, similar, signs are in use in Armenian: the U+0559 ◌ՙ ARMENIAN MODIFIER LETTER LEFT HALF RING and the U+055A ◌՚ ARMENIAN APOSTROPHE.

Breve and inverted breve are also shaped like half rings, respectively, the bottom and the top half of a circle.

Other uses

The ring is used in the transliteration of Abkhaz to represent the letter ҩ. It may also be used in place of the abbreviation symbol ॰ when transliterating the Devanagari alphabet.