and the meaning of the resulting compound must be left to be dealt with in the Syntax; here, only the forms of compounds can be considered.
ii. (1) The second element of a compound has its initial softened; thus: n‑n háf-ddydd ‘summer’s day’; a‑n háwdd-fyd ‘pleasure’; a‑a gw̯ýrdd-las ‘greenish blue’; n‑a pén-gam ‘wry-headed’.
The reason is that the first element in Brit, ended in a vowel, as in Brit. Maglo-cunos > W. Mael-gwn; so *samo-díi̯ē(u)s > W. haf-ddydd; *katu-markos > W. cad-farch, etc. In these, as generally in the Ar. languages, the first element is the stem. In Kelt. when the stem ended in a consonant an ‑o- was added to it; thus the stem *kun- ‘dog’ is in compounds *kuno‑, as Brit. Cuno-belinos > W. Cyn-felyn; W. cyn-ddaredd ‘rabies’ < *kuno-daŋgu̯ríi̯ā < *‑dhn̥ɡu̯hri-: Lat. febris < *dheɡu̯hri‑s, √dheɡu̯h- § 92 iii, cf. aren § 106 ii (1). This explains the suffix ‑ioni § 143 iii (21); it is a compound of a derivative in ‑i̯on- with *gnīmu‑; now *druki̯on-gnīmu- should give *drygni by the usual loss of stem endings; but *druki̯ono-gnīmu- > *drygion-ᵹnif > drygioni (since nᵹn > n § 110 ii (1)). When the second element began with a vowel, contraction took place; thus *altro + au̯ō > *altrāuō § 76 v (5), cf. Gk. Dor. στρατᾱγός ‘leader of an army’ < *str̥to + ag̑‑, Brugmann² II i 79.
(2) When the first element ends in n or r, and the second begins radically with ll or rh, the latter is not softened: gwin-llan, per-llan, pen-rhyn see § 111 i (1); so gwen-llys L.G.C. 8, eurllin D.G. 13, etc.; similarly, though less regularly, in loose compounds: hên llew, hên llys, pur llawn § 111 i (1).
When a compound is consciously formed both ll and l are found thus ysgafn-llef D.G. 37 ‘light-voiced’, but eur-len D.G. 109 ‘cloth of gold’, geir-lon do. 110 ‘of merry word’; ir-lwyn do. 504, per-lwyn do. 518.
iii. The following adjectives generally precede their nouns, and so form compounds, mostly loose, with them:
(1) prif ‘chief’, as prif lys w.m. 1, prif-lys r.m. 1 ‘chief court’, prif ẟinas w.m. 179 ‘chief city’, prif gaer ib. ‘chief castle’; y prif ddyn ‘the chief man’. It cannot be used as an ordinary adj.; such a phrase as *dyn prif does not exist.
(2) hên, as hên ŵr or hén-wr ‘old man’; hên ddyn id., also hén-ddyn whence E. quoth Hending; Hén-llan Ỻ.A. 105, Hén-llys etc., hên ŷd Jos. v 11, yr hên ffordd Job xxii 15, yr hên derfyn Diar.
