The character Å (å) is derived from an A with a ring. It is a distinct letter in the Danish, Norwegian, Swedish, and Walloon 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.
The character ? (?; a Latin U with overring, or krou?ek in Czech Republic) is a grapheme in the Czech language preserved for historic reasons, which identifies a vowel shift. For example, the word for "horse" used to be written kó?, which evolved, along with pronunciation, into kuo?. Ultimately, the vowel [o] disappeared completely, and the uo evolved into ?, modern form k. The letter ? now has the same pronunciation as the letter ú (long [u:]), but changes to a short o when a word is morphed (e.g. nom. k -> gen. kon?, nom. d?m -> gen. domu), thus showing the historical evolution of the language. ? cannot occur in initial position. However, ú occurs almost exclusively in initial position or at the beginning of a word root in a compound. These characters are used also in Steuer's Silesian alphabet. The [uo] pronunciation has prevailed in some Moravian dialects, as well as in the Slovak language, which uses the letter ô instead of ?.
The ring is used in some dialects of Emilian-Romagnol to distinguish the sound /?/ (å) from /a/ (a).
? has been 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 has been used in the Lithuanian Cyrillic alphabet promoted by Russian authorities in the last quarter of the 19th century with the letter / used to represent the /w?/ diphthong (now written uo in Lithuanian orthography).
? and ? are used in the ISO 233 romanization of the Arabic alphabet. A fat?ah followed by the letter (w?w) with a suk?n (?) is romanized as a?. A fat?ah followed by the letter (y?') with a suk?n over it (?) is romanized as a?.
Ring upon e (e?) is used by certain dialectologists of the Walloon language (especially Jean-Jacques Gaziaux) to note the /?/ vowel typically replacing /i/ and /y/ in the Brabant province central Walloon dialects. The difficulty of type-writing it has led some writers to prefer ë for the same sound.
The standalone (spacing) symbol is ˚ RING ABOVE. The unrelated, but nearly identical degree symbol is ° DEGREE SIGN.
Although similar in appearance, it is not to be confused with the Japanese handakuten (゜ KATAKANA-HIRAGANA SEMI-VOICED SOUND MARK), a diacritic used with the kana for syllables starting with h to indicate that they should instead be pronounced with [p].
Unicode encodes the underring at ?̥ COMBINING RING BELOW
The underring is used in IPA to indicate voicelessness, and in Indo-European studies or in Sanskrit transliteration (IAST) to indicate syllabicity of r, l, m, n etc. (e.g. r? corresponding to IPA ). R with ring below, L with ring below, R with ring below and macron, and L with ring below and macron were actually proposed for Unicode because of their use in Sanskrit transliteration and the CSX+ Indic character set. However, the proposal was rejected, because they are already encoded as sequences.
In Romagnol, e? is used to represent /?/ in diphthongs, e.g. Santarcangelo dialect ame?ig [a'm?i?] 'friend', ne?ud ['n?ud] 'naked'. In Emilian, e? can be used to represent unstressed /?/ in very accurate transcriptions.
Half rings also exist as diacritic marks, these are characters ?͑ COMBINING LEFT HALF RING ABOVE and ?͗ COMBINING RIGHT HALF RING ABOVE. These characters are used in the Uralic Phonetic Alphabet, respectively for mediopalatal pronunciation and stron onset vowels. These characters may be used in the International Phonetic Alphabet, denoting less and more roundedness, as alternatives to half rings below ?̜ COMBINING LEFT HALF RING BELOW and ?̹ COMBINING RIGHT HALF RING BELOW. They are here given with the lowercase a: a? and a?, a? and a?.
ẚ LATIN SMALL LETTER A WITH RIGHT HALF RING is similar in appearance but differs from a? because its compatibility decomposition uses ʾ MODIFIER LETTER RIGHT HALF RING instead of ?͗ COMBINING RIGHT HALF RING ABOVE.
Other, similar signs are in use in Armenian: the ?ՙ ARMENIAN MODIFIER LETTER LEFT HALF RING and the ?՚ ARMENIAN APOSTROPHE.
The ring as a diacritic mark should not be confused with the dot or ?ͦ COMBINING LATIN SMALL LETTER O diacritic marks, or with the degree sign °.