πλατ-ύς;—RV *plₑth- > Armen. layn ‘broad’;—(without l, § 101 ii (2)) RF *pₑthē- > Lat. patē-re, etc.
(2) Other combinations are unpronounceable or difficult; thus u̯i̯ cannot be sounded before a cons.; in that case i̯ drops. Generally i̯, u̯ drop between consonants, see iv above.
ix. Some roots have more than one ungraded form; thus radical ā may stand beside radical ō, as in *arā- or *arō- ‘scratch, bite; plough, dig’: Lat. arā-re has F *arā- of the first, Gk. ἄροτρον has R *arə- of the second. The F of both, with ‑d- extension, occurs in Lat. rād-o, rōd-o. Beside ā we have sometimes to assume a, as in Skr. rádati ‘scratches, digs’ (not ə here, which gives i in Skr.). In many cases all the forms cannot be explained without assuming an alternation of long and short vowel in the root; this may have come about by false analogy. Another common form of root alternation is *tēu̯‑: *teu̯ā- or *g̑hēi̯‑: *g̑hei̯ā- (Lat. hiā-re); see vii (5).
Note.—Ablaut is not to be confused with the changes due to accentuation or other causes in the derived languages, such as the shortening of unacc. ā in Brit. § 74, or the loss of a vowel in such a word as cawr § 76 iii (4), which would be *cur if the loss were primitive § 76 ii (1).
Keltic vowels
in British and Welsh
§ 64. From what has been said in §§ 57–62 we arrive at the following vowel system for Pr. Kelt.:
| Short vowels | a e i o u |
| Long vowels | ā ī ū |
| Short diphthongs | ai ei oi au eu ou |
| Long diphthongs | āi ūi āu, īu |
| Short vocalic | l̥ m̥ n̥ r̥ |
The Short Vowels.
§ 65. i. The short vowels a, e, o remain unchanged in W.; see examples in § 58; so Latin a, e, o; unless affected by other vowels §§ 67–70. The exceptions are the following:
