A verb in the Quendi and Eldar essay from 1959-60 glossed “follow”, derived from primitive ✶ap-pata “walk behind, on a track or path” (WJ/387), with primitive pp aspirating and then becoming voiceless spirants, with ph pronounced as a long [ff].
Conceptual Development: The Gnomish Lexicon of the 1910s had similarly formed G. obra- “follow; succeed” based on G. ob “after” (GL/62), precursor to S. ab “after”.
In WJ/387, the verbal stem is given as aphad-, and the etymology as *ap-pata. If we follow the latter, the verb should perhaps read aphada-