SUMMARY
Languages differ as to which sounds are permissible to combine to form onset sequences. The aim of this article is to test two versions of the theory of sonority hierarchy to examine to what extent that they can make correct predictions about permissible onset sequences in Jordanian urban Arabic. It also aims at testing articulator-based feature theory to examine its capability to account for permissible onset sequences in the language in question. Findings of the study have shown that the sonority theory seems to fail to predict some occurring onset sequences in Jordanian urban Arabic and to make wrong predictions about some other missing sequences. Some sequences violate the minimal sonority distance, but they are found in Jordanian urban Arabic while some other sequences satisfy the minimal sonority distance, but they are not found in this language. The results have also shown that the articulator-based feature theory fails to account for permissible onset sequences in Jordanian urban Arabic.