D? (titlecase form; all-capitals form D?, lowercase d?) is the seventh letter of the Gaj's Latin alphabet for Serbo-Croatian (Bosnian, Croatian, Montenegrin and Serbian), after D and before ?. It is pronounced . D? is a digraph that corresponds to the letter Dzhe (?/?) of the Serbian Cyrillic alphabet. It is also the tenth letter of the Slovak alphabet. Although several other languages (see below) also use the letter combination D?, they treat it as a pair of the letters D and ?, not as a single distinct letter.
Note that when the letter is the initial of a capitalised word (like D?ungla or D?emper, or personal names like D?emal or D?amonja), the ? is not uppercase. Only when the whole word is written in uppercase, is the ? capitalised.
In Gaj's Latin alphabet (used for Serbo-Croatian), when the text is written vertically rather than horizontally (on signs, for instance), d? is written horizontally as a single letter; in particular, d? occupies a single square in crossword puzzles. Also, in cases where words are written with a space between each letter, d? is written together without a space between d and ?. These characteristics are also shared by Lj and Nj. Similarly, when a name beginning with D? is reduced to initial, the entire letter is initial, not just D. For example, D?enan Ljubovi? becomes D?. Lj. and not D. L. This behaviour is not the case in Slovak, where it is split into D/d and ?/?.
Czech does have the sound d, but in native Czech words it only occurs as a replacement of [t] before other voiced consonants. Therefore, [t] and [d] are written in native words using the same letter ?. This is not possible in loanwords, and Czech adopted the D? orthography in this case (for example d?us). In this case, the two letters are always split when text is written vertically. Lithuanian and Latvian similarly use D? without considering it a separate letter.
Letter "D?" is found in Unicode at code points U+01C4 (uppercase, ?), U+01C5 (titlecase, ?), and U+01C6 (lowercase, ?). Unicode representations of the letter are very rarely used in digital media, which tends to favor the corresponding two-character combinations. Manufacturers of computer keyboards and typewriters for Croatian users typically do not provide a single key for the letter. X keyboard extension provides
latinunicode keyboard layouts for entering Unicode representation of the letter on standard Croatian keyboard.