I quote (please note the capitalized T indicates the emphatic t):

"Since it becomes clear that Tagha (=Ta'a) (with all other Koranic deviations) is a borrowing from the Syro-Aramaic T'a, its meaning can consequently be found among the equivalent semantics field appropriate to this context. It follows from the context that the meaning to be retained is the one cited in Manna (289b f.) under (6) (nasiy) (to forget). Accordingly, this verse does not say "man is rebellious", but "man forgets".

Previously, he wrote that the modern use of the unusual verb Tagha was "due exclusively to this misread Koranic word". The etymological Arabic equivalent of Aramaic T'a is Da'a (generated by sonorization of the Syro-Aramaic emphatic T to Arabic emphatic D with simultaneous sound-shifting). The diacritical point that makes ayn into ghayn has no justification and the Syro-Aramaic verbal root T'a is rendered in this way (T - ayin - aleph).