the tenth letter of the alphabet in English and other modern languages, is, in its origin, a comparatively late modification of the letter I. In the ancient Roman alphabet, I, besides its vowel value in ibdem, litis, had the kindred consonantal value of modern English Y, as in iactus, iam, Iouem, iustus, adiuro, maior, peior. Some time before the 6th century, this y-sound had, by compression in articulation, and consequent development of an initial ‘stop’, become a consonantal diphthong, passing through a sound (dj), akin to that of our di, de, in odious, hideous, to that represented in our phonetic symbolization by (dz). At the same time, the original guttural sound of G, when followed by a front vowel, had changed to that of palatal g (j, gj), and then, by an advance of the point of closure, had passed through that of (dj), to the same sound (dz); so that i consonant and the so-called g ‘soft’ came to have, in the Romanic languages, the same identical value. In Italian, this new sound is represented by g before e and i, gi before a, o, and u. Thus, L. gestus, Iesus, iam, iocare, iudicem, are represented in Italian by gesto, Gesù, già, giocare, giudice. But in the other Romanic languages, the letter I was retained with the changed sound, so that, in these, i consonant and g ‘soft’ were equivalent symbols, distinguished only by derivation. In OF. the foregoing words were gest, Iesu, ia, ioer, iuge.

In OE., i consonant, so far as it was used, had (as still in all the continental Germanic languages) its Latin value (j), equivalent to OE. de, di, or e before certain vowels; thus we find iá, iól, iow, iú, iudod, iung, as occasional spellings of the words commonly written deá, deól, eow, deó (dió, diú), deoddd (diodod), deong (diong, diung). This was especially the case with foreign proper names and other words known through Latin, as Ianuarius, Iob, Iofes (= Jove), Iudéa, Iudéisc, iacinb, and the ethnic name Iótas, Iútan (rarely Eotas), now rendered ‘Jutes’. But the French orthography introduced by the Norman Conquest brought in the Old French value of i consonant = g ‘soft’ (dz); a sound which English has ever since retained in words derived from that source, although in French itself the sound was subsequently, by loss of its first element, simplified to (z).

From the 11th to the 17th c., then, the letter I i represented at once the vowel sound of i, and a consonant sound (dz), far removed from the vowel. Meanwhile, the minuteness and inconspicuousness of the small , and its liability, especially in cursive writing, to be confounded with one of the strokes of an adjacent letter, had led in mediæval Latin and general European writing, and thus also in English, to various scribal expedients in order to keep it distinct. (See I.) Among these, an initial was often prolonged above or below the line, or both; a final was generally prolonged below the line, and in both cases the prolonged part or ‘tail’ came at length in cursive writing to be terminated with a curve; thus arose the forms , , . The ‘dot’, used to individualize the minuscule i, was also used with the tailed form, and thus came the modern j, j. But this was at first merely a final form of i, used in Latin in such forms as ‘filij’, and in numerals, as j, ij, iij, vj, viij, xij. It was very little used in English, where y had previously been substituted for final i; and it was not till the 17th c. that the device of utilizing the two forms of the letter, so that i, i, should remain as the vowel, and j, j, be used for the consonant, was established, and the capital forms of the latter, J, J, were introduced.

The differentiation was made first in Spanish, where, from the very introduction of printing, we see j used for the consonant, and i only for the vowel. For the capitals, I had at first to stand for both (as it still does in German type, and in all varieties of Gothic or Black Letter); but before 1600 a capital J consonant began to appear in Spanish. (See, for example, Minsheu's Spanish Dictionary of 1599, where I and J are strictly distinguished, though the I and J words are put in one series.) In German typography, almost from the first, some printers employed a tailed form of the letter or j initially, to distinguish the consonant sound; but this was by no means generally established till much later. According to Watt (Bibliotheca Britannica), Louis Elzevir, who printed at Leyden 1595-1616, is generally credited with making the modern distinction of u and v, i and j, ‘which was shortly after followed by the introduction of U and J among the capitals by Lazarus Zetzner of Strasburg in 1619’. In England, individual attempts to differentiate i and j were made already in the 16th c., as by Richard Day, who printed books in London after 1578, and George Bishop, who printed the translation of La Primaudaye's French Academie in 1586, with i, j, u, v, differentiated as in modern use, but had no capital J or U. The J j types are not used in the Bible of 1611, nor in the text of the Shakespeare Folio of 1623 (but see JIG); these have I i for both values; but the latter has a capital Italic J in headlines in the proper names John, Juliet, Julius, and in the colophon, list of actors, etc., thus showing a tendency to use this (in its origin merely an ornamental variety of I) as a J. In Cotgrave's French-English Dictionary printed in 1611 (and in the reprint of it in 1632), the Roman type used for the French has no capital J, and uses I with both values, but it has the small j which is regularly used in the French words: thus Iustice, Ajuster. On the other hand, the italic type, in which the English is printed, has no small j, and uses i for both vowel and consonant; it has the two capitals, I and J, but uses them indiscriminately for the consonant: thus Ioyau: m. A Jewell; Ioyaulier: m. A Ieweller. Frequently J is used also for the vowel: thus Ingenieusement: Jngeniously; Ingenieux: Ingenious. Thus even when the types I and J were at hand, their use was not yet regulated. But during the decade which followed 1625, J, j, J, j, appear to have been gradually added to all founts of type, and the present usage of restricting I i to the vowel, J j to the consonant appears to have been generally established soon after 1630. (See, under U and V, the similar differentiation of U u vowel, and V v consonant, from the earlier V v initial, u medial and final.)

But though the differentiation of I and J, in form and value, was thus completed before 1640, the feeling that they were, notwithstanding, merely forms of the same letter continued for many generations; a vestige of it is still seen in the practice of many persons, who in script write the I form for both and and in the omission by printers of J and U from the signatures of the sheets of books. In Dictionaries, the I and J words continued to be intermingled in one series down to the 19th c. Dr. Johnson, indeed, under the letter I, says ‘I is in English considered both as a vowel and consonant; though, since the vowel and consonant differ in their form as well as sound, they may be more properly accounted two letters’. Nevertheless, he proceeds to treat them practically as one, his first word I being followed by Jabber; Jam by Iambick, and this by Jangle; while the three last words of I are Juxtaposition, Ivy, Jymold. The same practice was followed by Todd, and by Richardson 1820, and even in some later dictionaries. Joddrell in 1820, Webster in 1828, separate I and J, as independent letters. The name of the letter, now jay (dzei), was formerly jy (dzai), riming with I, and corresponding to French ji; this is still common in Scotland and elsewhere.

In printing manuscripts or reprinting books produced before the differentiation of I and J, the earlier I has been treated in two different ways. The earlier editors, in most cases, introduced the modern usage into their texts, changing the I of the archetype, when it stood for the consonant, into J. Later editors more usually aim at reproducing the actual form of the original, and retain I with its twofold value. As our quotations are, in the main, from printed editions of MSS., and in some cases from later editions of printed books, they necessarily reflect these differences of editorial practice, and often show J before the 17th c.; it is to be remembered that this is usually due to the edition quoted, not to the original scribe or printer. But in our chronological lists of ‘Forms’, which precede the Etymology and Senses, these editorial J's have been disregarded, and the contemporary I alone given down to the date when J was actually in use.

In some modern editions of MS. or Black-letter books, in which the minuscule i of the original text is reproduced, we yet find a capital J introduced. This arises probably from the circumstance that the MS. or Italic J, or Black-letter J, is more like a J than an I in appearance, and is actually still used both for I and J.
No word beginning with J is of Old English derivation. Many are from Latin, chiefly through French; some from Greek, and a few from Hebrew and Arabic. There are also numerous modern words from distant languages, Eastern or Western, as jaguar, jalap, jerboa, jungle, junk. Besides these, many familiar or colloquial words of recent appearance and obscure history begin with this letter. On account of the phonetic equivalence of i consonant (i.e. j) and g ‘soft’ in words from Romanic, while in native English words, as girl, get, g was ‘hard’, there was a considerable tendency in Middle English to substitute i (= j) for g in words from French, as in gemme, iemme, gentil, ientyl, gest, iest, (and occasionally a counter tendency to use g for i (j), as in iet, jet, geat, maiestie, majesty, magestie), of which traces still remain in gest, jest, sergeant, serjeant, jelly from Fr. gelée, etc.

The regular and practically uniform sound of the letter J in English is the consonantal diphthong (dz). In the word hallelujah (also spelt halleluiah) it has the sound of Roman i-consonant (j). The same sound is retained in proper names or alien terms from German and other languages in which the Roman value of j is retained, as Jena (jeiona), Jaeger, Joachim, Jungfrau, junker, Janos, Jaroslav, Jassy. In a few French words, distinctly recognized as alien, j has the French sound (z), as déjeuner, jeu d'esprit. In the transliteration of Oriental names, as jat, Jehangir, Jenghiz, Juggernaut, Jumna, etc., j is used with its English value.

I. 1. The letter. The plural appears as Js, J's, js, j's.
[1573-80 BARET Alv. I heading, Now as concerning I consonant, which oftentimes vniustly vsurpeth the sound and place of G: me thinke it hath small reason: or rather I may say it is verie absurd, and much against both Art and reason.] 1591 PERCIVALL Bibl. Hispan., Gram, Bjb, j somewhat like the French Desja, joieux, jouer, but best like the Hebrew with his point on the right horne, or sh in English, as Ojo, osho. 1599 MINSHEU Span. Gram. 7 There be three kindes of I in the Spanish, that is, small i, Greeke y, and j, Jota or consonant... J jota or j consonant, which this toong taketh of the Arabique, is pronounced as in French Jamais, Deja, Jehan, in English like sh, as Jardin, a gardin, shardin. Ibid. 8 X is..pronounced like J consonant, and the Spaniard often writeth one for another. c1620 A. HUME Brit. Tongue iv. (1865) 13 For distinctiones of both sound and symbol, I wald commend the symbol and name of i and u to the voual sound;..the symboles of j and v to the latin consonantes, and their names to be jod and vau; as, vain jestes. Ibid. v. 16 And j, for difference of the voual i, written with a long tail, I wald wish to be called jod or je. 1755 JOHNSON s.v. I (the letter): J consonant has invariably the same sound with that of g in giant; as jade, jet, jilt. 1896 A. WHYTE Bible Characters 190 Esau..carved E. and J. into a true lover's knot under the handle of it. 1897 A. LANG in Longm. Mag. June 184 We carry the tails of our J's..below the line.