(: Gk. ἀφρός ‘foam’, Ir. imrim ‘storm’); without metathesis and with i̯ lost, Bret. Van. ebr, Corn. ebron, ebbarn; again, with metath., W. nwyf-re ‘sky’ < *neib- < *nebhi̯o‑; the root is *enebh‑, of which *embh- is FV, and *nebh- is VF; with ‑l- suffix, § 90. (W. nef ‘heaven’ is however from √nem- ‘curve’ hence ‘vault’, as shown by Bret. neñv, Ir. nem; also seen in W. nant ‘vale’ < *nm̥‑t‑.)
vi. i̯ drops before i or e, see iv, v, above; cf. § 75 ii (2).
Interchange of consonants
Consonant Alternation.
§ 101. i. Comparison of the derived languages points to certain alternations of consonants in Pr. Aryan; they are mostly the result of dialectal variation, and of the accidents of consonant combination. The same causes produced the same results after the dispersion; and while some of the alternations mentioned below may be primitive, others are certainly later, and some comparatively recent. Three kinds of alternations may be distinguished: (1) the consonant alternates with zero; (2) the manner of articulation varies; (3) the place of articulation varies.
ii. The cases where the consonant alternates with zero are the following:
(1) Initial s- before a consonant is variable; thus Gk. στέγος, Lith. stógas ‘roof’, Skr. sthágati ‘conceals’: Gk. τέγος, Lat. tego, W. to ‘roof’; √(s)theɡ‑,—Ir. scaraim, W. ysgaraf ‘I separate’ Lith. skiriù id.: Lat. caro ‘flesh’, orig. ‘piece (of flesh)’, Gk. κείρω, Skr. kr̥ntáti ‘cuts’: √(s)qer‑;—W. chwech ‘six’ < *su̯ek̑s: Armen. vec̣ < *u̯ek̑s;—Lat. spargo, E. sprinkle: Gk. περκνός, W. erch ‘speckled, grey’ < *perq‑, § 97 v (3). This treatment of s- persisted long after the dispersion; and many of the examples found are undoubtedly cases of the dropping or the adding of s- in the derived languages. In Kelt. s- seems to have been added and dropped with a freedom hardly equalled elsewhere.—As ‑s was an extremely common ending in Ar., it is natural to suppose that ‑s st- would be confused with ‑s t‑, so that it would not always be easy to decide whether the initial had s- or not. But some scholars regard the s- as a “preformative” or more or less meaningless prefix; see Schrijnen KZ. xlii 97 ff.
(2) A consonantal sonant after an initial consonant was sometimes dropped. Thus W. chwech, Gk. ῾ϝεξ < *su̯ek̑s: Lat. sex, Goth. saihs < *sek̑s;—Gk. πλατύς, W. llydan, √plethē- ‘spread out, stretch’: without ‑l‑, Lat. patēre, Gk. πετάννυμι, W. edau ‘thread’;—W. brau ‘brittle’
