In revisiting Bolozky's [Bolozky, Shmuel, 1979. "On the new imperative in colloquial Hebrew." "Hebrew Annual Review" 3, 17-24] and Bat-El's [Bat-El, Outi, 2002. "True truncation in colloquial Hebrew imperatives." "Language" 78(4), 651-683] analyses of colloquial Hebrew imperatives, the article argues for restricting Imperative Truncation to the morphologically-triggered process of #tV prefix elision (or even to just #t prefixes). Elision of "e" and "i" in imperatives is claimed to be effected by the general, phonetically-motivated elision of the same vowels in casual speech. The prominence and sonority of the vowel a protects it from elision in imperatives, and short forms like kum "get up!" are not derived from their takum counterparts, but rather borrowed from the normative register.
Available at: http://works.bepress.com/shmuel_bolozky/4/