(2) dydd ‘day’ < *díi̯ēus: Lat. diēs, and dyw ‘day’ in dyw Gwener ‘on Friday’ etc. from an oblique case (Ar. gen. *diu̯és, *diu̯ós), pl. dïeu < Brit. *di̯éues § 100 ii (1), beside dïeuoeẟ § 128 i, and dyẟẏeu Ỻ.A. 51, r.b.b. 9, re-formed from the sg., Mn. W. dyddi̯au, now the usual form, though tridi̯au is still in common use.
Bluitinet a hir dieu (t ≡ ẟ) b.b. 56 ‘years and long days’; deugein niheu Ỻ.A. 21 ‘forty days’; seith nieu r.b.b. 54; deugain nïeu D.G. 198, etc.
(3) duw ‘god’, O. W. duiu- § 78 iv (2) < *dei̯uos (: Lat. deus) is the same word as the above with different vowel grades § 63 vii (4). The Ml. pl. dwyw̯eu Ỻ.A. 73 is formed from the old sg.; geu-dwyeu also occurs do. 44 with loss of w̯; the Mn. pl. duw̯i̯au is a second re-formation.
(4) di̯awl ‘devil’, pl. dïefyl § 100 ii (1), also a late pl. di̯awl(i̯)aid (loss of i̯ by dissim. is usual) ; the pl. dieifl used by Gr.O. is artificial, as possibly the sg. diafl. Wm.S. invented a new sg. diafol, which was adopted in the Bible, and so is considered more respectable than the genuine form.
(5) blwyddyn ‘year’, pl. blynedd, blwyẟyneẟ, blynyddoedd § 122 iv (2), § 125 v (1).
(6) aren pl. eirin § 106 ii (1), new pl. arennau; eirin ‘plums’, new sg. eirinen.
(7) pared, pl. parwydydd § 130 i (4); ffêr ‘ankle’, pl. (old dual) uffarnau, ucharnau § 96 iv (2), late pl. fferau, fferi. Other cases of anomalous vowel changes in § 125 v, § 117 iii.
(8) One or two examples generally quoted of irregular plurals are due to haplology, § 44 iv, and are irregular in the late period only. Mn. W. cydymaith ‘companion’, pl. cymdeithion; Ml. W. sg. cedymdeith w.m. 10, pl. cydymdeithon do. 1;—Mn. W. credadun ‘believer’, pl. credinwyr, a corrupt re-formation from credini̯ol for creduni̯ol, § 77 ix, for credaduni̯ol; Ml. W. credadun, pl. credadunion m.a. i 566.
Nouns with no Plural.
§ 133. The following nouns are used in the sg. only:—
i. Many abstract nouns, simple, as gwanc ‘voracity’, llwnc
