Mn. W. G.R. discarded k on the principle of “one sound one letter”, p. 20. But the decisive factor in its banishment from the Welsh alphabet was its replacement by c in Salesbury’s N.T., published the same year (1567). This being one of the many innovations “quarrelled withall” in his orthography, Salesbury, in the Prayer Book of 1586 gave his reason for the substitution: “C for K, because the printers haue not so many as the Welsh requireth,” Llyfryddiaeth 34. It is curious to note that a letter which was thus superseded because of its greater prevalence in Welsh than in English was classed 160 years later among “intruders and strangers to the Welsh language”, Gormesiaid a dieithriaid i’r Iaith Gymraeg, S.R. (1728) p. 1.
§ 19. i. The characters b, d, g, in O.W. represented initially the modern sounds b, d, g; but medially and finally they stood for the mutated sounds f, ẟ, ᵹ, as in gilbin juv., Mn. W. gylfin ‘beak’, guirdglas m.c. ≡ gw̯ỿrẟᵹlas, Mn. W. gwyrddlas ‘greenish blue’. Medially and finally f was also represented by m, though in this case the spirant was doubtless nasalized then, as it is still normally in Breton; thus nimer ox. ≡ niṽer, Mn. W. nifer ‘number’, heitham ox., Mn. W. eithaf ‘extreme’.
ii. (1) In Ml. W., b represented the sound b, but no longer the sound f.
(2) The sound f was written in Early Ml. W. u or v, w and f; thus in b.b., niuer 7 ≡ nifer; vaur 21 ≡ fawr ‘great’; sew 45 ≡ sef ‘that is’; dihafal 20 ≡ dihafal ‘unequalled’. We also find ff, as affv 21 ≡ a fu ‘who has been’, bariffvin 53 ≡ barfwyn ‘white-bearded,’ tiff 50 ≡ tyf ‘grows’.
As u and v also represented the vowel ü, and as u, v, and w represented w as well, the orthography of this period is most confusing.
(3) In Late Ml. W. the sound f was written medially u or v and fu; finally it was represented by f regularly (the few exceptions which occur, e.g. in w.m., being due to mechanical copying). Thus, Ỻ.a., vy 2 ≡ fy ‘my’; llauur 3 ≡ llafur ‘labour’; kyfuoethawc 55, Mn. W. cyfoethog ‘rich’; gyntaf 3 ‘first’, dywedaf 3 ‘I say’, ef 3 ‘he’, etc. u and v continued to be used medially for f during the Early Mn. period; but G.R. has f everywhere, and was followed by Dr. M. in the 1588 Bible, which fixed the Late Mn. orthography.