(of a wave), hair of the head, border (of a country)’, briger ‘hair of the head’ < *brīk- for *prīk‑, metath. for *krīp- > W. crib ‘comb, crest, ridge (of a roof)’: Ir. crīch ‘boundary of a country’ < *qrī-q-u̯o- broken redupl., √qerēi- ‘separate, divide, cut off’: Lat. crēna ‘notch’, crista ‘crest’, crīnis ‘hair of the head’;—Ir. droch ‘wheel’: W. tro ‘turn’;—Ir. gēc: W. cainc ‘branch’ < *k̑n̥q‑: Skr. s̑ā́khā ‘branch’;—W. gast ‘bitch’: ci ‘dog’ § 96 ii (3).—Cf. W. Grawys, Garawys ‘Lent’ § 138; < Lat. quadragēsima. Still later is the softening of the initial of an adverb, and of a proclitic, as dy ‘thy’; these are regarded as mutated forms, and are not mutated further (except occasionally by false analogy).
(3) Alternations like the above occur also in suffixes; as *‑tro‑: *‑dhro- and *‑tlo‑: *‑dhlo‑.
(4) Though l and r are not mixed indiscriminately, several doublets occur in which they alternate, as √g̑hu̯er- / g̑hu̯el- § 92 iv. These alternations may have originated, as suggested by Meillet, Intr.² 143, in reduplicated forms in which, by dissimilation, r may become l, or even n. Thus √ɡu̯erē- ‘devour’ gives *ɡu̯er-ɡu̯el‑, *ɡu̯ₑn‑ɡu̯r‑, etc., also with ɡ for ɡu̯ by dissim.; thus Gk. βιβρώσκω, Lat. vorāre, W. barus ‘greedy’ < *ɡu̯ₑr‑: (broken redupl.) Gk. ἔβροξε, Ml. H. G. krage, Ir. brāge, W. breuant ‘windpipe’ < *ɡu̯r̥̄ɡ-n̯t‑: (full redupl.) Lat. gurgulio, O. H. G. querechela, Gk. γάγγραινα: Lat. gula.
iv. The place of articulation might vary.
(1) The different gutturals sometimes alternate. Thus, q/k̑: √leuq/k̑‑: Skr. rócate ‘lights, shines’, roká‑ḥ ‘bright’, Lith. láukti ‘to expect’, with *‑q‑: Skr. rús̑ant- ‘bright, white’, Lith. lúszis ‘lynx’ with *‑k̑‑;—the suffix *‑qo‑: *‑k̑o‑, as Skr. maryaká‑ḥ (márya‑ḥ ‘young man’) with *‑q‑: Skr. yuvas̑á‑ḥ (yúvan- ‘young’) with *‑k̑‑: Lat. juvencus, W. ieuanc ambiguous;—√ak̑‑/oq- § 63 v (2);—√k̑ei‑: √qōi‑: √qu̯ei̯ē‑, see Walde s.v. civis. For a large number of examples see Brugmann² I 545 ff. After s‑, ‑q- predominates, § 84 Note 2; and k̑/q alternate, as Skr. chinátti ‘cuts, severs’ < *sk̑‑: Lith. skë́dziu ‘I separate’ < *sq‑, √sk̑(h)eid‑/sq(h)eid‑.
ɡu̯h/g̑h:—Lat. fī-lum ‘thread’ < *ɡu̯hī‑: W. gī-au ‘nerves, sinews’ < *g̑hī‑;—W. gw̯res, Gk. θερμός, etc. < *ɡu̯h‑, § 92 iii: Lith. žarýjos ‘glowing coals’, Alb. zjar̄ ‘fire’ < *g̑h‑;—W. gw̯elw ‘pale’, Lith. geltas ‘tawny’ < *ɡu̯h‑: Lith. želiù green, W. glas ‘green’ < *g̑h, § 92 iii.
Exactly the same change of position as the last is involved in the alternation of u̯ and i̯, which occurs in some roots, as √g̑hēu‑: √g̑hēi‑ ‘yawn’.
(2) The Ar. consonant series p, t, k, q, qu̯ is not a line with p and qu̯ as loose ends, but as it were a circle, in which p and qu̯ approach one another. qu̯ combines the back with the lip position, and the shifting of the stop to the latter position makes it p. It is not surprising therefore that qu̯ became p in some languages as W., Osc.-Umb., Gk., or that under certain conditions p > qu̯, § 96 iv. Already in Ar. there seem to be some cases of p alternating with qu̯, and even
