I knew this site would suck me in sooner or later. So here goes onehanded typing with a baby in the other hand..this won’t be a long post.
Lisa is right that Iraqi speakers have prothesis with initial sC clusters, but according to Broselow’s 1983 article, sCC clusters are adapted as siCC, so she gives the example [sitrit] for ‘street’. She relates this to the general rule of three-consonant cluster epenthesis in Iraqi of O –> i / C _ CC. Under this scenario, the first vowel is truly epenthetic, present for syllabification reasons, but the second (which Broselow does not transcribe in her examples) must be one of those transitional vocoids. Hence the length difference?
Broselow, Ellen (1983). Nonobvious transfer: on predicting epenthesis errors. In S. Gass & L. Selinker (eds.) Language Transfer in Language Learning, 269-280. Rawley, MA: Newbury House.