i:Short, i ([§ 10]).
Long, ei ([§§ 16]. [17]).
e: Short, wanting.
Long, ê ([§§ 6]-8).
æ: Short, aí ([§ 20]).
Long? (perhaps the ai in [§ 22]).
a: Short, a ([§§ 3]. [4]).
Long, â ([§ 5]).
ǫ: Short, wanting.
Long, ô ([§§ 11]. [12]).
u: Short, u ([§§ 13]. [14]).
Long, û ([§ 15]).
Difthongs:
iu: [§§ 18]. [19].
ai: [§ 21].
au: [§ 25].

B. HISTORICAL SYSTEM (Ablaut-Series).

§ [29]. The Gothic vowels, as regarded from a historico-etymological point of view, may be groupt into a number of series of related vowels. The vowels belonging to such a series may interchange in formations with the same root; in the formation of tenses and in the verbal and nominal derivation all vowels of the same series may occur, but not such as hav nothing in common with that series. This change of vowels within a series is calld ablaut (or gradation), the series themselvs ablaut-series. The ablaut-series ar most perceptibl in the verb. The relation between the vowels of the same series is not a fonetic but a historical one; to establish it, we must pass beyond the limits of the Germanic languages and take recourse to the comparativ grammar of the Indo-Germanic languages. The Gothic ablaut-series as appearing in verbal inflection ar these (cp. [§ 172] et seq.):

§ [30]. I. Series: ei ai i (aí).

Exampls: reisan (urreisan), rais, risum, risans, to rize; urraisjan, to raiz; urrists, f., resurrection; —þeihan, þaíh, þaíhum, þaíhans, to thrive; —wait, I know; pl. witum; weitan, to see; weitwôds, witness; miþ-wissei, conscience; witubni, n., knowledge; —lais, I know; lubja-leisei, f., wichcraft; lists, f. (?), stratagem; laisjan, to teach.

Note. The i of this series is the proethnic Germanic i mentiond in [§ 10], b.

§ [31]. II. Series: iu au u (aú).

Exampls: giuta, gaut, gutum, gutans, to pour; gutnan, to pour (intr.); —liugan, laug, lugum, lugans, to lie; liugnja, m., liar; liugn, n., lie; analaugns, hidn; laugnjan, to deny; —galaubjan, to believ; galaubeins, belief; liufs, dear; lubô, f., luv; lubains, f., hope; —siuks, sick; saúhts, f., sickness; —driusan, to fall; drausjan, to drop (tr.); drus, m., fall; driusô, f., slope.

Note. The vowel û is rare in this series; cp. lûkan, to lock ([§ 173], n. 2); anabûsns (? [§ 15], n. 1), command, < biudan.

§ [32]. III. Series: i (aí) a u (aú).