köken: From Middle High German ez ne sî denne, a stereotypical negatively exceptive sentence. The simple negation ne had been gradually vanishing since medieval times and had been dropped entirely by Luther's time. Since the disappearance of ne, the negative function has been assumed by denn (or dann), meaning "then" (i.e. "at that time"), which was originally facultative but gradually came to serve as…
Ich bin um 8 Uhr da, es sei denn, der Zug hat Verspätung / dass der Zug Verspätung hat.
köken: Represents a univerbation of Middle Dutch het ne si, het en si, from Old Dutch hit ne sī (“if it not be”) (attested as hinase); thus closely related to hetzij.
köken: From Arabic إما لَ (ʾimmā lā), equivalent to إما (ʾimmā, “if even”) + لَ (lā, “not”) cognate with Hebrew לֹא (lo). Likely adapted to form the compound אִי ('i, “not having, not being”) + לְמַלֵּא (lemalé, “to fulfill”).