Ar. *uqsō, whence O.H.G. ohso, Skr. ukṣā (Av. uxš- implies ‑q‑); the pl. ỿchen (< Ar. *uqsénes, whence Skr. ukṣáṇaḥ, E. oxen) has ỿ from u unaffected, § 66 i.
u does not become ei; deifr as pl. of dwfr is doubtful (m.a. i 556) except as a late and artificial form; see Silvan Evans s. v.
vi. When any of the above changes takes place in the ultima, a in the penult becomes e; see kedyrn, elyrch, pelydr, Selyf, esgyrn above. o also became e, as gosod ‘to set’ gesyd ‘sets’, liable to become ỿ before st, as Ml. W. ebestyl, ebystyl < apostolī, sg. abostol < apostolus. In Ml. W. the affection extended, as in the last example, to the ante-penult.
vii. The ei due to affection as above, also ei from ek or eg, had open e̦, and was thus distinct from original ei which had close ẹ. The former (e̦i) gives ei, ai; the latter (ẹi) gives w͡y § 75 iii (1).
§ 70. Non-ultimate affection. i. a and sometimes o in the syllable which is now the penult became e when the following syllable had ī or ĭ (now i or ɥ), except where the ĭ was itself affected to e, § 68. Thus cerydd ‘reprimand’ < *karíi̯o(s) beside caredd ‘fault’, Ir. caire, < *karíi̯ā;—Ml. W. gwedy ‘after’, O. W. guotig;—Ml. W. pebyll ‘tent’ < *papíli̯o < Lat. pāpilio;—Ebrill < Aprīlis;—cegin < coquīna; melin < molīna; etc. In Ml. W. the affection extends over two syllables, as ederyn ‘bird’, Mn. W. aderyn, pl. adar.
o seems to undergo the change chiefly after a labial or before a guttural, where it might have become a if unaffected.
The restoration of a in the antepenult in Mn. W. is due to the vowel in that syllable becoming obscure because unaccented, in which case it was natural to re-form etymologically.
ii. (1) Before i̯ the same change took place, and a and o appeared as e in O. W.; but the e was further affected by the i̯, and became ei in Ml. and Mn. W.; thus Mariānus > O. W. Meriaun gen. iii. > Ml. W. Meirẏawn r.b.b. 81, Mn. W. Meiri̯on;—so O. W. Bricheniauc a.c. 895, Mn. W. Brycheini̯og;—O. W. mepion gen. xii, Mn. W. meibi̯on ‘sons’. See § 35 ii.
In the dialect of Powys ceili̯og ‘cock’, ceini̯og ‘penny’ are pronounced cel̯iog, ceni̯og. This is perhaps a simplification of ei, § 78 v, rather than old e retained.
