Where this comes from
12 · The Assyrians of Urmi: a background · a plain-language guide to Assyrian (Sureth) grammar
All of it is Geoffrey Khan, The Neo-Aramaic Dialect of the Assyrian Christians of Urmi, vol. 1 (Brill, 2016) — the introduction, §0.1–0.2 (pp. 1–11), §0.5–0.7 (pp. 22–40) and §0.9 (pp. 42–44). The dates, counts and census figures are his, each with his own sources cited on those pages.
What it leaves out is most of it: the tables placing Urmi among the 150-odd North-Eastern Neo-Aramaic dialects, the village-by-village phonetics, the history of scholarship from 1855 onwards, and Khan's account of his own fieldwork. Every Assyrian word above is his, in this guide's plain spelling.