I is the ninth letter; in the old Runic alphabet it was called íss or ice (Skálda 176), and represented by ? (ís köllum brú breiða of the Runic poem), a form borrowed from the Greek or Latin: but ‘stunginn Íss’ (?) was in later Runes used to represent e.

A. PRONUNCIATION, SPELLING.—I is either a vowel (i), or consonant (j), called joð: these are here treated separately: 1. the vowel i is sounded either short (i) or long (í), the short (i) like Engl. hill, prolonged with a breath; but it is almost certain that in olden times it was sounded short, as in Engl. wit. 2. the long (í) is sounded as Engl. e or ee in evil, feet. 3. the j is sounded as Engl. y before a vowel, jata, jarð, jól, as yata, yard, yole. The oldest writers bear witness to the use of j as a consonant; thus Thorodd says,—i þá er hann verðr fyrir samhljóðanda settr, Skálda 164; and the second grammarian,—en ef hljóðstafr (vowel) er næstr eptir hann, þá skiptisk hann í málstaf (consonant), svo sem já, jörð eða jór, 170; and Olave Hvítaskáld,—i ok u hafa því fleiri greinir, at þeir eru stundum samhljóðendr, sem í þessum orðum, iarl and uitr, 176; but in syllables beginning with j (ja, jo, ju) in old alliterative poetry it always stands for the vowel, from the earliest poems down to the 15th century, e. g. jörð or ægi—iðja-græna, Vsp. 58; viltú nokkut jötuninn eiga | ýtum görir hann kosti seiga, Þrymlur 2. 2; Ölmóðr hafði annan dag | járnið þetta at sýna, Skíða R. 64, which, as now pronounced, would sound harsh, since in modern poetry syllables beginning with j cannot be used alliteratively with any other letter, cp. Pass. 37. 1, 10, 40. 8, 46. 3, 11, etc.; only in such words as eg (jeg), eta (jeta) can i serve both as a vowel and consonant, see Pass. 6. 2; but jeg in 5. 5, 10, (the verse 6 of the same hymn is a poetical licence); so also the name Jesús is now and then used alliteratively with a vowel, 47. 18, 21; the hymns of the Reformation follow the same usage. The pronunciation of j seems therefore to have changed: in early times it was probably similar to Engl. e in ear, tear, hear; an additional proof of this is, that the oldest spelling was, as in Anglo-Saxon, ea, eo …; and Thorodd himself probably wrote ea, e. g. eafn, eárn, earl, for jafn, járn, jarl, see his words: in old poets ea sometimes makes two syllables, e. g. in the verse cited in Skálda 164 (of A. D. 1018); as also in the name Njáll (Niel), which is dissyllabic in the verses, Nj. ch. 136, 146. At a still earlier time j was probably sounded purely as a vowel. II. in ancient MSS. i serves for both i and j; in MSS., esp. of the 15th century, j is used ornamentally for initial i, e. g. jnn = inn, as also in the double ij = í, e. g. tijd = tíð, mijtt = mítt, the j was introduced into print only in the last year of the eighteenth century. 2. an i is often inserted in MSS., esp. after g, k, so as to mark the aspirate sound, e. g. gieta = geta, giæta = gæta, kiær = kær, etc.: in inflexions it is also more correct to write eyjar, bæjar, than eyar, bæar:—ji is not written, but pronounced, e. g. vili (= vilji), but vilja.

B. CHANGES.—The i and e are exchanged in many root syllables, but i is usually the older, e the later if not the modern form, as, if and ef, brinna and brenna, tvinnr and tvennr, þrimr and þremr, miðil and meðal, snimma and snemma, gingu and gengu, fingu and fengu, tigr and tegr: the article varies between enn and inn:—the inflex. -endi and -indi:—Norse MSS. spell mek, þek, sek, = mik, þik, sik (e. g. Thom. Cd. Holm.); -ligr and -legr, gagnligr and gagnlegr: for the inflexive e and i see introduction to letter E (signif. B), p. 114:—i for y in old MSS., in firir, ifir, mindi, skildi, minni (mouth), minnast (to kiss, mouth):—i and u are interchanged in inflexion, as, morginn and morgunn, vandill and vöndull; but esp. in the adjective inflexions -igr and -ugr, blóðigr and blóðugr, auðigr and auðugr. II. the j in most instances originates from an e, either through absorption or contraction, as in jór (q. v.), or through the dissolution or breaking of e, as in jörð (q. v.); again, the i as initial is in most instances caused by absorption; as of n in í (in) and compds; of v or b in íllr (evil) and compds; of d in some compds in í- from ið;—in Gothic there is only a single word (eisarn, i. e. ísarn = iron) with a long í initial. III. by comparison with other Teutonic languages it is seen that a radical initial i or j has in the Scandinavian been dropped in a few words, while it has been kept in Gothic, Saxon, and German, thus Icel. ár, Goth. jêr, Engl. year, Germ. jahr; Icel. ungr, Goth. juggs, Engl. young; Icel. ok, Goth. juk, Engl. yoke, Germ. joch, Lat. jugum; Icel. ami, ömurligr, and O. H. G. jamar, Germ. jammer; Icel. upp, Goth. jup, Engl. up; Icel. ér (ye), Goth. jus; Icel. ostr (a cheese), cp. Engl. yeast: in two words, jarteign and jurt, both of them probably foreign, the j stands for w: on the other hand, because of the resolution or breaking of vowels (Gramm. p. xxix, bottom), words which in Engl. and Germ. begin with e are in Icel. often to be found under j, thus Icel. jörð (old Scot. yerth) = Engl. earth, Germ. erde: there are also a few stray words,—jata (a manger) for eta, jeta for eta, jeg for eg (ek). IV. the Icel. í answers to Ulf. ei (rísa, Goth. reisjan), to mod. Germ. ei in zeit, Engl. i as in time, Icel. tími; in early German the diphthongs ei and í were, as in Icelandic, distinguished (zît, îsarn, = mod. zeit, eisen). V. in mod. Dan. in a few words the Icel. short i is represented by an e, thus Icel. við, liðr, viðr, siðr, biðja, limr, vinr, sin, = Dan. ved, led, ved, sed, bede, lem, ven, sene, probably owing to the fact that the old Danish pronunciation of i was not the same as the present Icelandic.