A "crazy rule" in Zenaga

As part of what seems to be a solo documentation effort, Ahmadou Ismail has been posting some very interesting tidbits on Zenaga (in Arabic). The dialect reflected differs in some ways from the one reflected in Catherine Taine-Cheikh's publications. One of the more conspicuous differences is in the fate of proto-Berber *z. For Taine-Cheikh, *z > ẕ̌ in general (a slightly lowered ž), but *zt > Z (a tautosyllabic geminate zz). In Ahmadou Ismail's dialect, *zt > zz as with Taine-Cheikh, but otherwise *z > h, eg tihigrarin "tarawih prayers" vs. Taine-Cheikh's təẕ̌əgrärən, hīmmar "lamb" vs. Taine-Cheikh's iẕ̌iʔmär, awahiđ̣ "rooster" vs. äwäẕ̌uđ̣, yahinha "he sold" vs. yäžžənẕ̌äh. This leads to systematic alternations between h and zz; synchronically, Ismail's dialect of Zenaga has the "crazy rule" ht > zz. This is nicely illustrated by "he knew" (Taine-Cheikh: yuʔgäẕ̌) plus the direct object personal pronoun clitics:

• "he knew me": yūgah-i
• "he knew you m.": yūgah-ku
• "he knew you f.": yūgah-kam
• "he knew him": yūgaz-zu
• "he knew her": yūgaz-zað
• "he knew us": yūgah-ānag
• "he knew you m.pl.": yūgah-kūn
• "he knew you f.pl.": yūgah-kimmið
• "he knew them m.": yūgaz-zin
• "he knew them f.": yūgaz-zincað (maybe; not quite sure how چَّٰ is supposed to be read)

For forms without assimilation, compare, as posted by someone else on the same group (Omar Sidi Mohamed), "he was owned by" (Taine-Cheikh yənšäg):

• "he was owned by me": yiššag-i
• "he was owned by you m.": yiššak-ku
• "he was owned by you f.": yiššak-kam
• "he was owned by him": yiššak-tu
• "he was owned by her": yiššak-tað
• "he was owned by us": yiššag-ānag
• "he was owned by you m.pl.": yiššak-kūn
• "he was owned by you f.pl.": yiššak-kamað
• "he was owned by them m.": yiššak-tan
• "he was owned by them f.": yiššak-tinyað