*sundī or *sindī. The ‑u- and ‑i- are undoubtedly for ‑o- and ‑e- before ‑nd- § 65 iii (1); we arrive, therefore, at *sondos, *sondā for hwn, hon, *sendod for hyn neut., and *sondī or *sendī for hyn pl. (In the Coligny Calendar sonno and sonna occur, Rhys CG. 6, but the context is obscure or lost.)
The most probable explanation of the above forms seems to be that they are adjectives formed from adverbs of place, which were made by adding a ‑d(h)- suffix, § 162 vi (2), to *sem‑, *som‑: Skr. samá‑ḥ ‘same’, Gk. ὁμός, Ir. som ‘ipse’. The form of the adverb would be similar to that of Skr. sa-há ‘in the same place together’ < *sm̥-dhe; but the Kelt. formations have the full grades *sem‑, *som- (instead of the R‑grade *sm̥‑) and the demonstrative meaning (‘in this place, here’). For the formation of an adj. *sendos from an adv. *sende cf. Lat. supernus: superne, and cf. the transference of the flexion to the particle ‑te in Lat. is-te, etc.
It is probable that coming after its noun the form of the adj. was m. *sondos, f. *sondā, neut. *sondod, pl. m. *sondī giving W. m. and neut. hwn, f. hon, pl. hyn. This agrees with the fact that neut. adj. hyn after a noun is an innovation ii (1).—Before a noun the form would be *sendos etc., whence the Ir. article (s)ind. This survives in only a few phrases in W.—The substantival form would also be m. *sendos, f. *sendā, neut. *sendod, pl. m. *sendī which would give W. m. hyn, f. *hen, neut. hyn, pl. hyn. We have seen above, iv (1), that ir hinn was m. in O.W., but was already beginning to be ousted by hirunn (for *ir hunn), as *henn had perhaps been already replaced by honn, for in Corn. the forms are m. hen (= W. hynn), f. hon (= W. honn). The result is that hyn remains as the neut. subst.; but the m. and f. substantives hynn, *henn were changed to hwnn, honn on the analogy of the adjectives.
The form hwnnw comes from a derivative in ´‑ii̯o- of the adj. *sondos; thus *sóndii̯os > hunnoiẟ § 75 iv (2) > hunnuiẟ > hwnnw § 78 i (1), (2). The fern. *sóndii̯ā would also give the same form, which actually occurs as f.: ir bloidin hunnuith cp. ‘that year’; honno is therefore a re-formate on the analogy of hon; so the last syll. of hynny § 78 i (1).
ar is prob. formed in a similar manner from an adv. with the suffix ‑r which was mostly locative, Brugmann² II ii 735. The stem might be *an‑ § 220 ii (11); thus *an-ro‑s > *arr > ar.
Pronominalia.
§ 165. i. Pronominalia expressing alternatives are substantival and adjectival, definite and indefinite.
Subst. def.: y naill … y llall ‘the one … the other’; pl. y naill … y lleill ‘these … the others’. In Ml. W. the first term is y neill or y lleill, thus y lleill … y llall ‘the one …