boot and stem theory
Most textbooks define a "stem-changing rule" in which the stem of some Sicilian verbs changes in the present tense forms of the first, second and third-person singular and the third-person plural. Elsewhere, the stem remains unchanged.
For example, Gaetano Cipolla defines the following rule (Mparamu, p. 64):
If the stem vowel is i, it changes to e as in: aspittari-aspettu.
I would define the rule differently. On this page, I suggest that all Sicilian verbs are stem-changing verbs.
Specifically, all Sicilian verbs appear to have an unstressed "stem" and a stressed "boot."
Using Dr. Cipolla's examples of aspittari and sèntiri, there is an unstressed i in stem and a stressed e in the boot of both verbs:
The verbs allungari and mòriri both have an unstressed u in stem and a stressed o in the boot:
Similar "boot and stem" patterns can be found in all Sicilian verbs. For example, the verbs parrari and rispùnniri -- which are not normally classified as stem-changing verbs -- both have an unstressed vowel in stem and a stressed vowel in the boot:
After accounting for this pattern, there are very few irregular verbs in the Sicilian language. And because the language is so regular, it is relatively simple to create a software tool that automatically conjugates Sicilian verbs, like the one that I created for Cchiù dâ Palora.