In contrast, the letter j does not have this distinction in these languages, with a dot only on the lower case character: J j, but the dotless j does exist in Unicode: ?. That letter is sometimes used in mathematics with a combining hat to indicate a unit vector.
In English and most languages using the Latin script, the capital i is dotless (I) while the lowercase i has a dot on it. (i)
In some fonts, if the lowercase letters fi are placed adjacently, the dot-like upper end of the f would fall inconveniently close to the dot of the i, and therefore a ligature glyph is provided with the top of the f extended to serve as the dot of the i. A similar ligature for ffi is also possible. Since the forms without ligatures are unattractive and the ligatures make the i dotless, such fonts are not appropriate for use in a Turkish setting. However, the fi ligatures of some fonts do not merge the letters and instead space them next to each other, with the dot on the i remaining. Such fonts are appropriate for Turkish, but the writer must be careful to be consistent in the use of ligatures.
|Unicode name||LATIN CAPITAL LETTER I||LATIN SMALL LETTER I||LATIN CAPITAL LETTER
I WITH DOT ABOVE
|LATIN SMALL LETTER|
|UTF-8||73||49||105||69||196 176||C4 B0||196 177||C4 B1|
|Numeric character reference||I
|Named character reference||İ||ı, ı|
In normal typography, when lower case i is combined with other diacritics, the dot is generally removed before the diacritic is added; however, Unicode still lists the equivalent combining sequences as including the dotted i, since logically it is the normal dotted i character that is being modified.
Most Unicode software uppercases ? to I and lowercases ? to i, but, unless specifically configured for Turkish, it lowercases I to i and uppercases i to I. Thus uppercasing then lowercasing, or vice versa, changes the letters.
In the Microsoft Windows SDK, beginning with Windows Vista, several relevant functions have a NORM_LINGUISTIC_CASING flag, to indicate that for Turkish and Azerbaijani locales, I should map to ? and i to ?.
In the LaTeX typesetting language the dotless ? can be written with the backslash-i command:
\i. The ? can be written using the normal accenting method (i.e.
Dotless ? (and dotted capital ?) is handled problematically in the Turkish locales of several software packages, including Oracle DBMS, PHP, Java (software platform), and Unixware 7, where implicit capitalization of names of keywords, variables, and tables has effects not foreseen by the application developers. The C or US English locales do not have these problems. The .NET Framework has special provisions to handle the 'Turkish i'.
Many cellphones available in Turkey (as of 2008) lacked a proper localization, which led to replacing ? by i in SMS, sometimes severely distorting the sense of a text. In one instance, a miscommunication played a role in the deaths of Emine and Ramazan Çalçoban in 2008. A common substitution is to use the character 1 for dotless ?. This is also common in Azerbaijan (see also translit), but the meaning of words is generally understood.
John Cowan proposed disunification of plain Ii and capital letter dotless I and small letter I with dot above to make the casing more consistent. The Unicode Technical Committee had previously rejected a similar proposal because it would corrupt mapping from character sets with dotted and dotless I and corrupt data in these languages.
In some Ectaco translators, the letter ? was also treated as I (e.g. TRAFIK ⟨traffic⟩, when it is normally TRAF?K).
Dotted and dotless i are used in several other writing systems for Turkic languages:
The dotless ? may also be used as a stylistic variant of the dotted i, without there being any meaningful difference between them. This is common in Irish, for example, but is considered simply an omission of the tittle rather than a separate letter. In some of the Athabaskan languages of the Northwest Territories in Canada, specifically Slavey, Dogrib and Chipewyan, all instances of i are undotted to avoid confusion with tone-marked vowels í or ì.
Both the dotted and dotless I can be used in transcriptions of Rusyn to allow distinguishing between the letters ? and ?, which would otherwise be both transcribed as "y", despite representing different phonemes. Under such transcription the dotted ? would represent the Cyrillic ?, and the dotless I would represent either ? or ?, with the other being represented by "Y".