Wurdahuzdą: Proto-Germanic dictionary

suffix verb Weak class 1 forms Weak class 1 verbs from nouns and adjectives, especially denominals meaning ‘act as, use, provide, or be associated with X’ and factitives meaning ‘make X, cause to become X’ forms causative verbs from strong verbs, with the sense ‘cause to X’ From a Proto-Germanic j-present stem + the infinitive ending *-aną. The j-present suffix had several pre-Germanic sources that fell together in PGmc to form a single suffix: among them were inherited and derived Proto-Indo-European *-yé/ó- or *-ye/o-presents, denominals from o-stem nouns in PIE *-e-yé/ó-, and deverbal causatives in PIE *-éye/o- Ringe 2017: 200–201. In denominal and factitive verbs, *-janą reflects the Germanic continuation and leveling of PIE y-present and denominative formations. Compare Sanskrit denominatives in -यति and, more broadly, Greek and Latin derived-verb classes continuing or remodeling the same *-yé/ó- and *-eye/o- complex. In causatives, the source is specifically PIE *-éye/o-, as also reflected in Sanskrit causatives in -अयति and, with later branch-specific remodeling, in formations such as Proto-Slavic *-iti causatives and some Greek -έω, and Latin -ēre and -īre verbs Fulk 2018: 294–96Ringe 2017: 200–201, 281–84. Conjugation

The suffix varies as *-janą /*-ijaną based on Siever’s Law: the basic *-janą form is used after a “light” syllable (a short vowel followed by a single consonant), and otherwise, the form becomes *-ijaną. In causatives from strong verbs, the root normally has the o-grade corresponding to the strong preterite singular, while a root-final obstruent affected by Verner’s Law appears in its voiced alternant because the original causative suffix *-éye/o- was accented. Thus the causative often combines the preterite-singular vowel of the strong verb with the Verner alternant of the root-final consonant, as in *rīsaną (‘to scale; move vertically (either up or down)’) / *rais (1st person singular preterite) → *raizijaną (‘to cause (someone, something) to rise; raise’).