certainly accords with the fact that the augment, an accented preverb, is always followed by forms with secondary endings.
ii. The Ar. athematic stems, excepting those of a few common verbs, ended mostly in the long vowels ‑ā‑, ‑ē‑, ‑ō‑. As medial ‑ō- became ‑ā‑, and ‑ē‑ became ‑ī‑ in Kelt., these characteristics were reduced to two, ‑ā- and ‑ī‑. The vowel had F-grade in the sg., R-grade in the pl., as in Gk. ἵστημι < *sí-sthā-mi, pl. 2. ἵστατε < *sí-sthə-the. The Kelt, forms of the 1st sg. pres. were therefore *‑ā-mi, *‑ī-mi. As the form was mostly unaccented, and unaccented ‑ā- > Brit, ‑a- § 74, the prevailing Brit, forms were *‑a-me, *‑ī-me. These give the W. ‑af, -if, the latter comparatively rare, § 173 ii, and now obsolete. Examples: (1) Ar. *dí-dō-mi ‘I give’ > Kelt. *(p)ró (di‑)dā-mi > Brit. *ró-da-me > W. rhoẟaf ‘I give’;—(2) Ar. *dhí-dhē-mi ‘I put’ > Kelt. *(p)ró (di‑)dī-mi > Brit. *ró-dī-me, which would give W. *rhoẟif ‘I put’. But the latter ending was rare, and was supplanted by ‑af, the result being, in this case, that two verbs became one: rhoẟaf ‘I give, I put’. The reduplicating syllable was probably lost by haplology. Only the vowel of the syllable dropped in dodaf ‘I give, I put’ < *dó-tāme or *dó-tīme < *dó d(i)-dōmi or *dó dh(i)-dhēmi: Gk. δίδωμι or τίθημι. Usually dodaf is ‘I put’; for dod ‘give’ see Ps. lxxii 1, Gr.O. 87.
iii. (1) The accented forms of the 3rd sg. *‑ā́-ti, *‑ī-ti give the W. strong forms ‑awd, ‑id. These are used at the head of the sentence, like accented verbs in Skr. The introduction of ‑h- before the ending in Ml. W., where not etymological as in trenghit (ngh < ŋk), is analogical, and partly artificial. The second form tended to oust the first in this case, as seen in O.W. prinit ‘buys’ for *prinaut < Brit. *prinā́-ti: Ir. cren(a)id; see § 201 i (4). The ‑id form with the initial of the affixed pron. fo, thus *‑id‑f, gave *‑it‑ff and then ‑iff, the dial. ending, by loss of the t as in the 2nd pl., see § vii. The West Gwyn. ‑ith has recent th for ff.
Ml. W. ‑yd in ëyt, § 173 vi (1), is from *‑etī < *‑e‑tai the middle 3rd sg. ending: Gk. φέρεται; see § 193 x (1).
(2) But the usual form of the 3rd sg. in W. is the stem without or with vowel affection; this comes from the unaccented injunctive form; thus câr loves < Brit. *kara‑t; rhydd ‘puts’ < Brit. *ró-dī‑t. The latter, being more distinctive, spread; thus rhydd ‘gives’ instead of *rhodd < *ró-da‑t.
iv. (1) The Ar. thematic endings *‑ō, *‑ēis, *‑ēit would become *‑ū, *‑īs, *‑īt in Kelt.; and these in W. would all drop after affecting the vowel. The 1st and 2nd sg. so formed were lost because they were not distinctive; but prob. the 3rd sg. added to the number of affected stems forming the W. 3rd sg.
(2) The thematic injunctive ending ‑et of unaccented verbs dropped without affecting the vowel; thus Ar. inj. *bher‑e-t ‘bears’ gives Kelt. *kóm beret > W. cymer ‘takes’, and Kelt. *áti beret > W. adfer ‘restores’, etc. It is found not only in compound, but in simple verbs, as cêl ‘conceals’ < *kelet, rhed ‘runs’ < *retet, etc., because