Arabic /ē/ gets colloquial: the case of al-Kisā'ī

My description of Khalaf's reading in the previous post applies to all readings transmitted from Ḥamzah ibn Ḥabīb al-Taymī of Kūfa: Khalaf, Khallād, Idrīs al-Ḥaddād, and Isħāq al-Warrāq. There is one other set of readings with final -ē, however: those transmitted from ʕAlī ibn Ḥamza al-Kisā'ī of Kūfa, through his students Abū al-Ḥārith and al-Dūrī. Here's an example (sūrat al-Shams, al-Dūrī's reading):

This set shows two interesting differences for the words examined before:

• Verbs with medial /ē/ in the Ḥamzah tradition simply have [ā]; contrast Ḥamzah's xēba خاب "he lost" with al-Kisā'ī's xāba. In other words, medially *aya and *awa both become ā, just like in the standard Classical pronunciation.
• Verbs with final /ā/ in the Ḥamzah tradition have /ē/, just like the ones with /ē/; contrast Ḥamzah's talāhā تلاها "it followed it" with al-Kisā'ī's talēhā. In other words, final *aya and *awa both become ē, whereas original *ā remains ā.

The latter development is phonetically quite counterintuitive - why would *awa become ē, when it didn't even contain any front vowel? But it makes more sense when you look at it on a morphogical rather than phonological level. Arabic has a huge number of final-y verbs, and a much smaller number of final-w verbs. In the rather common 3rd-person perfect forms, they are indistinguishable. This makes it tempting to simplify the system by reducing the differences between the two classes, and in fact practically all modern Arabic dialects have taken this to its logical conclusion and simply conjugate all final-w verbs as if they were final-y: thus Algerian Arabic, for instance, has dʕa دعا, dʕit دعيت, yədʕi يدعي instead of daʕā دعا, daʕawtu دعوت, yadʕū يدعو. What al-Kisā'ī is doing looks like an early step along that road.

You may notice that another characteristic of this reading is also distinctly reminiscent of certain modern colloquials, in particular those of Syria: prepausal feminine -ah ة is pronounced -ih.