The letter J was used as the swash letter I, used for the letter I at the end of Roman numerals when following another I, as in XXIIJ or xxiij instead of XXIII or xxiii for the Roman numeral representing 23. A distinctive usage emerged in Middle High German.Gian Giorgio Trissino (1478–1550) was the first to explicitly distinguish I and J as representing separate sounds, in his Ɛpistola del Trissino de le lettere nuωvamente aggiunte ne la lingua italiana ("Trissino's epistle about the letters recently added in the Italian language") of 1524. Originally, 'I' and 'J' were different shapes for the same letter, both equally representing Script error, Script error, and Script error; but, Romance languages developed new sounds (from former Script error and Script error) that came to be represented as 'I' and 'J'; therefore, English J, acquired from the French J, has a sound value quite different from Script error (which represents the initial sound in the English word "yet").
In English, ⟨j⟩ most commonly represents the affricateScript error. In Old English, the phoneme Script error was represented orthographically with ⟨cg⟩ and ⟨cȝ⟩. Under the influence of Old French, which had a similar phoneme deriving from Latin Script error, English scribes began to use ⟨i⟩ (later ⟨j⟩) to represent word-initial Script error in Old English (for example, iest and, later jest), while using ⟨dg⟩ elsewhere (for example, hedge). Later, many other uses of ⟨i⟩ (later ⟨j⟩) were added in loanwords from French and other languages (e.g. adjoin, junta). The first English language book to make a clear distinction between ⟨i⟩ and ⟨j⟩ was published in 1633. In loan words such as raj, ⟨j⟩ may represent Script error. In some of these, including raj, Azerbaijan, Taj Mahal, and Beijing, the regular pronunciation Script error is actually closer to the native pronunciation, making the use of Script error an instance of a hyperforeignism. Occasionally, ⟨j⟩ represents the original Script error sound, as in Hallelujah and fjord (see Yodh for details). In words of Spanish origin, where ⟨j⟩ represents the voiceless velar fricativeTemplate:IPAblink (such as jalapeño), English speakers usually approximate with the voiceless glottal fricativeScript error.
In English, ⟨j⟩ is the fourth least frequently used letter in words, being more frequent only than ⟨z⟩, ⟨q⟩, and ⟨x⟩. It is, however, quite common in proper nouns, especially personal names.
In modern standard Italian spelling, only Latin words, proper nouns (such as Jesi, Letojanni, Juventus etc.) or those borrowed from foreign languages have ⟨j⟩. Until the 19th century, ⟨j⟩ was used instead of ⟨i⟩ in diphthongs, as a replacement for final -ii, and in vowel groups (as in Savoja); this rule was quite strict for official writing. ⟨j⟩ is also used to render Template:IPAslink in dialect, e.g.Template:Clarify span. The Italian novelist Luigi Pirandello used ⟨j⟩ in vowel groups in his works written in Italian; he also wrote in his native Sicilian language, which still uses the letter ⟨j⟩ to represent Template:IPAslink (and sometimes also [dʒ] or [gj], depending on its environment).
1 Also for encodings based on ASCII, including the DOS, Windows, ISO-8859 and Macintosh families of encodings.
Unicode also has a dotless variant, ȷ (U+0237). It is primarily used in Landsmålsalfabet and in mathematics. It is not intended to be used with diacritics since the normal j is softdotted in Unicode (that is, the dot is removed if a diacritic is to be placed above; Unicode further states that, for example i+ ¨ ≠ ı+¨ and the same holds true for j and ȷ).
Template:AnchorIn Unicode, a duplicate of 'J' for use as a special phonetic character in historical Greek linguistics is encoded in the Greek script block as ϳ (Unicode U+03F3). It is used to denote the palatal glideScript error in the context of Greek script. It is called "Yot" in the Unicode standard, after the German name of the letter J. An uppercase version of this letter was added to the Unicode Standard at U+037F with the release of version 7.0 in June 2014.
In the Wingdings font by Microsoft, the letter "J" is rendered as a smiley face (note this is distinct from the Unicode code point U+263A, which renders as ☺). In Microsoft applications, ":)" is automatically replaced by a smiley rendered in a specific font face when composing rich text documents or HTML email. This autocorrection feature can be switched off or changed to a Unicode smiley.
In the United Kingdom under the old system (before 2001) , a licence plate that begins with "J" for example "J123 XYZ" would correspond to a vehicle registered between August 1, 1991 and July 31, 1992. Again under the old system, a licence plate that ends with "J" for example "ABC 123J" would correspond to a vehicle that was registered between August 1, 1970 and July 31, 1971.