alä - without, except, other than, not, un-
(AED 1101)
Appleyard (1977:60) assumes the development *bälä > älä, which is hardly probable (it would be difficult to explain the loss of b- in that case, see EDG 37 and Arakelova 2001:28).
PS
*ˀilā/*ˀillā - besides, apart from
(Arakelova 2001:27)