Berber and not so Berber words in Tunisian Arabic

Not too long ago I finished reading Lotfi Sayahi's Diglossia and Language Contact: Language Variation and Change in North Africa. The book is a valuable contribution to the study of synchronic language contact between Tunisian Arabic, Standard Arabic, and French in Tunisia, with some coverage of the rest of the region as well. Unfortunately, when it briefly looks at Berber lexical influence on Arabic (pp. 135, 187), reflecting joint work with Zouhir Gabsi, its conclusions are rather over-hasty. Since this book is likely to become a standard point of departure for English speakers studying language contact in North Africa, I think it's worth correcting the record here even at the risk of being pedantic:

• fakru:n "turtle" and ferzazzu "wasp" really are Berber, though the -u:n suffix in the former was first added in dialectal Arabic (almost all Berber varieties have forms similar to Kabyle ifker/ikfer).
• garžu:ma "throat" is a very difficult word to etymologize, but may ultimately be Berber (compare Tuareg a-gurzăy), although it does bring to mind Romance forms such as French gorge.
• karmu:s "fig" is clearly derived from karm-a "fig tree", which is definitely not Berber, and seems to come from a narrowing of the meaning of Classical Arabic كرم karm "orchard" (see the brief discussion in Behnstedt & Woidich 2011:491). The suffix -u:s might theoretically be Berber, I suppose, but probably not; it's not widely attested across Berber, and it fits well with the widespread dialectal Arabic pattern of augmentatives in -u:-.
• sebsi: "pipe" is from Turkish sipsi.
• bu-telli:s "monster/nightmare" ("sleep paralysis", to be precise) is a compound involving bu- "possessor of" (originally "father of") plus telli:s (a kind of rug). The latter is well-attested within Arabic in the Middle East as well as in North Africa; its etymology is controversial, but it may derive from Latin trilicium "triple-twilled fabric".
• ḍabbu:ṭ "axilla" (ie "armpit") is evidently an expressive formation from Arabic إبط 'ibṭ. The widespread Berber word for this is rather taddeɣt (from which we get Maghrebi Arabic dəɣdəɣ "tickle").
• dagdag "to shatter" is a reduplicated form from Arabic دقّ daqqa "pulverize".

I don't have the time to check the rest of the reduplicated verbs he cites (tartar "to mutter", dardar "to muddy", maxmax "to nibble", maṣmaṣ "to rinse", sɛksɛk "to flow", tɛftɛf "to graze", and wɛdwɛd "to talk nonsense"), but maxmax and maṣmaṣ include phonemes with no regular proto-Berber sources, and I doubt any of them is really Berber in origin.

I don't mean to pick on the authors; notwithstanding this brief lapse, it's a good book, and worth reading. But I do want to hammer home to every linguist the message that etymology needs to be done properly. If you want to do etymology in a North African dialect, don't just assume that any word you don't recognize from Modern Standard Arabic or French is a Berber loanword; check other regional languages (especially Turkish), check existing publications on the subject, check the distribution of the word across different Berber and Arabic varieties. Etymology may not be a very trendy subject, but that doesn't mean it's easy.