Noeldeke 1886, 726 tentatively connected the Akkadian–Aramaic isogloss *tkl (considered to be a secondary derivation from PS *wkl) with PES *tkl “to fix, to fasten, to plant” . This comparison, implying that Ethiopian preserves the primary meaning “to fix, to be well-fixed, reliable” and undermining the derivation from *w-k-l, is discussed and rejected by Leslau in CDG 573.
PNWS *ykl ‘to be able’ may be related.
According to a broad consensus summarised in Kouwenberg 2010a, 454 and Kogan 2015, 101, Akk. takālu is a diachronically secondary verb going back to PS *wkl “to trust, to rely”. The same type of secondary root has been independently produced in Arabic and Aramaic. As reasonably argued by Kaufman 1974, 106, the high proliferation of *tkl in Aramaic (notably, in opposition to its modest presence in Arabic) may be due to Akkadian influence on Aramaic or even to a direct borrowing from Akkadian.