In cases where the F-grade has not survived, or has survived only in Indo-Iranian, where ā̆, ē̆, ō̆ all appear as ā̆, so that the quality of the vowel is unknown, it is usual to write it āˣ.
Examples: √dō- ‘give’: F: dawn ‘gift’ < *dō‑n‑; Lat. dō-num; Gk. δί-δω-μι.—V: rho-ẟ-ant ‘they give’ < *pro-d-n̥ti; Skr. dá-d-ati < *dé-d-n̥ti. √dhē- ‘put’:—F: Gk. τί-θη-μι;—V: rho-ẟ-ant ‘they put’. See § 179 ii.
√sthā- ‘stand’: R: gwa-sta‑d ‘level’ < *upo-sthə‑t‑; Lat. stā-tus; W. sa‑f ‘stand’ < *sthə‑m- § 203 vii (5);—F: saw‑dl ‘heel’ < *sthā‑tl‑.
√sē- ‘sow’:—R: had ‘seed’ < Ar. *sə‑t‑; Lat. să-tus.—F: hīl ‘progeny’, Ir. sīl < *sē‑l‑; Lat. sē-vi, sē-men.
(2) ə generally appears as a in the European languages, as in the above examples. (Cf. § 110 ii (2).) But in Gk. if the F-grade is ē or ō, the R-grade often appears as ε or ο. Elsewhere e beside a is probably to be explained as due to a variant of the root, with short vowel; thus W. tref, O. W. treb ‘homestead’ < *treb‑; Lat. trabs < *trəb‑; Gk. τέρεμνον, τέραμνον both < *terəb‑; √terē̆b‑.
vii. (1) As a rule the same morphological element could not contain two F-grade syllables, though, of course, a word, made up of more than one element, might. The diversity in different languages of words of the same origin is largely due to the preservation of various groupings of grades; see for example *qu̯etu̯er- in (4) below.
(2) A large number of roots were disyllabic. A characteristic form of Ar. root had a short vowel in the first syllable and a long in the second. A very common form of reduction was RR, i.e. R-grade of both syllables. When the consonant between the vowels was one of the sonants i̯, u̯, RR was ₑi̯ə, ₑu̯ə, which gave ii̯ə, uu̯ə; these were generally contracted to ī, ū respectively; we may call this contraction R². On the analogy of these it is assumed that RR ₑlə, ₑrə, ₑmə, ₑnə gave respectively R² l̥̄, r̥̄, m̥̄, n̥̄, § 61 ii, § 62 ii. The uncontracted RR forms also survived, as in Gk. παλάμη; < *pₑlə-mā, √pelā‑, beside W. llaw(f), Ir. lām < Kelt. *lā-mā < *pl̥̄-mā;—W. taradr ‘auger’, Ir. tarathar < ER *tₑrə‑tr‑, beside Gk. τέρετρον < FR *terə‑tr‑, √terē- ‘bore’;—W. rhaeadr ‘cataract’ < RR *rii̯ə‑tr‑, beside Lat. rīvus < R² *rī‑, √rei̯ā- ‘flow’. In many cases the ə dropped, see vi (1), as in Lat. palma < *pₑl(ə)-mā; we may denote this by R(R). Beside these we also have VR forms lə, rə, mə, nə; thus beside W. gwaladr ‘ruler’ < RR *u̯ₑlə‑tr‑, we have W. gw̯lad ‘country’, Ir. flaith ‘lordship’ < VR *u̯lə‑t‑, √u̯elē(i)- (: Lat. valēre, E. wield);—W. gw̯lân ‘wool’ < VR *u̯lən-ā, beside Lat. lāna, Skr. ū́rṇā < R² *u̯l̥̄n-ā;—W. rhann ‘share’, Ir. rann id. < VR *prə‑t-snā, beside Lat. part- < R(R) *pₑr(ə)‑t‑, beside Skr. pūr-t-ám ‘reward’ < R² *pr̥̄‑t‑, √perō‑;—W. ystrad ‘dale’, Gk. στρατός < VR *strə‑t‑, beside W. sarn ‘causeway’ < R(R) *stₑr(ə)n‑, beside Skr. stīr-ṇá‑ḥ ‘strewn’, Lat. strā-tus < R² *str̥̄‑, √sterō- ‘spread out’.—When the long vowel after l, r, m, or n was ā or ō we cannot distinguish in Kelt. between
