§§izt-z] Ablaut (Vowel Gradation) 45 §121. Goth.áu=(i) Germ, au, īndg. ēu (§ 00), as dat. sing, sunáu, to a son. = (2) Germ, au, Indg. ōu (§ 90), as ahtáu, eight.
		CHAPTER VII ABLAUT (VOWEL GRADATION) § 122. By ablaut is meant the gradation of vowels both in stem and suffix, which was caused by the primitive Indo-Germanic system of accentuation. See § 32. The vowels vary within certain series of related vowels, called ablaut-series. In Gothic, to which this chapter will chiefly be limited, there are seven such series, which appear most clearly in the stem-forms of the various classes of strong verbs. Four stem-forms are to be distinguished in a Gothic strong verb which has vowel gradation as the characteristic mark of its different stems: — (i) the present stem, to which belong all the forms of the present, (2) the stem of the preterite singular, (3) the stem of the preterite piural, to which also belongs the whole of the preterite subjunctive, (4) the stem of the past participle. By arranging the vowels according to these four stems, we arrive at the following system :—
				1. 11. 111. IV. I. ei áí i(aí) l(aí) II. iu áu u(aú) u(aú) III. i(aí) a u(au) u(aú) IV. i(aí) a ē u(aú) V. i(aí) a ē i(aí) VI. a ō ō a VII. ē ō ō δ
		NOTE.—On the difference between i and al, see §§ 67, 69; u and aú, see §§ 71, 73.