Английский Этимологический словарь - ache (v.)

- O.E. acan "to ache, suffer pain," from P.Gmc. *akanan, perhaps from PIE base *ag-es- "fault, guilt," perhaps immitative of groaning. The noun is M.E. жche, from O.E. жce, from P.Gmc. *akiz. The verb was pronounced "ake," the noun "ache" (by i-mutation, as in speak-speech) but while the noun changed pronunciation to conform to the verb, the spelling of both was changed to ache c.1700 on a false assumption of a Gk. origin.