Speech rhythm in the different Arabic dialects investigated has been consistently described as stress-timed. At the same time, there is preliminary evidence from perceptual experiments that listeners use speech rhythm cues to distinguish speakers from North Africa from those of the Middle East. In an attempt to elucidate the apparent contradiction, an acoustic investigation of the proportion of vocalic intervals and the standard deviation of consonantal intervals in six dialects (Morocco, Algeria, Tunisia, Egypt, Syria and Jordan) was carried out using procedures put forth by Ramus & al [1]. The results show that complex syllable and reduced vowels in the Western dialects , and longer vowels in the Eastern dialects seem to be the main factors responsible for differences in rhythmic structures. The paper also raises questions about the discrete or continuous natures of rhythm types.
Ramus, F.; Nespor, M.; Mehler, J., 1999. Correlates of linguistic rhythm in the speech signal. (Available from URL: http://www.ehess.fr/lscp/persons/ramus/pub.htm.)