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-ecer Inchoative verb-forming suffix.
A suffix indicating the production or becoming of a process. A merger of various endings in Latin, -escere, -iscere, and -ascere 'id.,' all of which come from a single inchoative suffix in Latin, -sc-. The inchoative suffix was more common in Classical Latin than in Proto-Romance, where its meaning waned as speakers increasingly saw it as simply another "stem-extender" on some verbs (see Manea 1971; Rudes 2011). From Proto-Italic *-sk-e/o- 'id.' From Proto-Indo-European *-sḱ-e/o- 'id.'
Asturian -ecer, Portuguese -ecer, -escer, Catalan -eix, French -is, Italian -isco, Aromanian -esc, Romanian -esc
Umbrian -sk-
Old Irish -c
Gothic *-h- (in fraihnen)
Lithuanian *-šý- (in prašýti), Old Church Slavonic *-si- (in prositi)
Sanskrit *-ch- (in pr̥chā́mi "to ask"), Avestan *-sa (in pərəsa "to ask")

"The productive descendants of [Proto-Indo-European *-sḱ-é/ó-] differ in meaning from branch to branch. In Anatolian, the suffix indicates repeated, habitual, or background action, or action applied to more than one object... The habitual or durative sense is also found in Homeric Greek... Other Latin verbs with the suffix, however, are inchoatives (indicating the beginning or inception of an action or state)... Several verbs having the suffix that are reconstructible for PIE refer to asking or wishing, indicating perhaps that the suffix also once had a desiderative function." ~ B. Fortson, Indo-European Language and Culture (2011)