62 Phonology [§ 136 root-syllable, a uniform interchange took place between the voiceless and voiced spirants, which may be thus stated:— The medial or final spirants f, þ, χ, xw, s regularly became to, đ, 5, gw, z when the vowel next preceding them did not, according to the original Indg. system of accentuation, bear the principal accent of the word. The ΰ, đ, g, gw which thus arose from Indg. p, t, k, q underwent in the Germanic languages all further changes in common with the t>, đ, 5, gw from Indg. bh, đh, gh, gh. Verner's law manifests itself most clearly in the various forms of strong verbs, where the infinitive, present participle, present tense, and preterite (properly perfect) singular had the principal accent on the root-syllable, but the indie, pret. plural, the pret. subj. (properly optative), and past participle had the principal accent on the ending, as prim. Germ. *w6rþō > OE. weorþe, I become = Skr. vártā-mi, / turn, pret. 3 sing. *wárþi > OE. wearþ, he became = Skr. va-várta, has turned, pret. ipl. *wurđumí>OE. *wurdum (wurdon is the 3 pers. pi. used for all persons) =±. Skr. va-vrtimá; past part. *wurđaná- > OE. worden = Skr. va-vrtāná-; OS. birid = Skr. bhárati, he bears, Goth, 2 sing, indie, pass, baíraza = Skr. bhárasē. Goth, baíranđ, OHG.berant = Skr. bháranti, they bear; present participle Goth. baírands,O.Icel. berandi, OE, berenđe, OS. beranđi, OHG. beranti, Gr. gen. φέροντα;. Or to take examples from noun-forms, &c., we have e. g. Skr. pitár-, Gr. πάτερ-= prim. Germanic *fađer-, Goth.fadar, OE. fæder, O.Icel. faðir, OS. fađer, OHG. fater,father; Gr. πλωτό?, floating, swimming, Goth, flōđus, OE. OS. flōđ, O.Icel. flōð, OHG. fluot, flood, tide; Skr. catám, Gr. Ι-κατόΊ-, Lat. centum = prim. Germanic *xunđom, older *xumđom, Goth- OE. OS. hund, OHG. hunt, hundred; Indg. *sw6kuros, Goth, swaíhra, OHG. swehur, father-in-law, beside Gr. Ικυρα, OE. sweger, OHG. swigar, mother-in-law; Gr. δέκα, Goth, taíhun, OS. tehan, OHG. zehan, ten, beside Gr. 8í*(£s,