Whenever one sees a triliteral verb with initial /t/, one suspects development somewhere from a T-stem of a fundamentally biliteral one. This common Aramaic verb probably derives from the identical and equally common Akkadian, which itself would appear to be a typical development from a T-stem of the common Semitic root wkl (i.e. Aramaic/Hebrew ykl, but "to trust" in Arabic) that otherwise appears in Akkadian as the very common noun waklu, aklu, "overseer". See also AIOA p. 106.