Abstract This is the first study that investigates polysyllabic shortening in Arabic. It aims to find out the extent to which Modern Standard Arabic employs this phonetic mechanism, which is usually associated with stress-timed languages. Data were collected from 10 Jordanian speakers reading 6 sets of words representing the six monophthongs in Arabic in a carrier sentence. Based on the acoustic analysis of 180 vowels, it was found that the vowels in monosyllabic words were significantly longer than their counterparts in polysyllabic words. However, the differences between the vowels in disyllabic and trisyllabic words were much smaller. Findings suggest that polysyllabic shortening is not invoked as a mechanism to maintain the stress-timed rhythm of stress-timed languages. Rather, it seems to be a universal phonetic feature that applies in different degrees that are commensurate with the rhythm of the language in question.