In my hometown, the small port of Dellys in north-central Algeria (and probably elsewhere for all I know), older women traditionally throw water after a family member who is departing for a long voyage. When I asked my oldest aunt (who speaks no language but Arabic) about this recently, she said it was to bring them safety – Arabic 'amān – on the road. The Berber word for “water” is, precisely, aman. The action reveals itself as originally a pun rather than a mere superstition – but one that only makes sense in the light of both languages at once, not Arabic or Berber alone. A useful case to bear in mind in trying to understand North African culture...
When Emir Abdelkader came to Dellys in 1840 and inquired about its defences against the French (who would occupy it four years later), he was allegedly told that the town places its trust in its saints: Sidi Abdelkader by sea, Sidi Soussan by land. In the account of Bennaamane (2011:61, citing Daumas and Fabar 1847:197), Emir Abdelkader reacted in a very modern way: he got angry at their superstition and pointed out that Algiers had not been saved by its "patron saint" Sidi Abderrahmane. But somewhere along the transmission of this account, a bit of metonymy has been misunderstood. The tomb of the supposed saint Sidi Abdelkader was located at the tip of a 700-metre-long peninsula next to the town, from which you can see any incoming ship for at least 20 km (map). That of Sidi Soussan was located at the top of the hill on whose side Dellys stands, and was such an obvious location for defenses that the French turned it into a blockhaus soon after. The speaker was using religious language, but his trust was as much in the scouts posted there as in the saints buried there.
Dellys (dəlləs, medieval Tadallas), owes its name to a common plant used in net-making and thatching (Ampelodesmos mauretanicus), locally called dalis (better known in Algeria as dis.) The name is not attested before the 11th century, and does not resemble its earlier Latin name (Rusuccurium, from Phoenician rus “head, cape”.) However, Murcía (2011) points out that the plant name is a good deal more ancient: a 5th-century work, Ars sancti Augustini pro fratrum mediocritate breviata, states that non-Latin regional words are barbarous, ut si quis dicat in latino sermone dellas pro carice, quod utique punicum est (“like if someone says in Latin dellas, which is undoubtedly Punic, in place of carex (sedge)”). Murcía reasonably takes the word to be Berber rather than Punic in origin: as he points out, forms similar to adlis for this plant are found all across northern Berber. But as Bennaamane (2011:22) points out, there is a comparable classical Arabic form in Lisān al-`Arab – dalas “the remains of plants and vegetables; land that bears plants after having been barren; plant that leafs after late summer” – so this could be an old Semitic loan into Berber too; more extensive comparative work is called for.
بن نعمان، اسماعيل. 2011. مدينة دلس (تدلس) : دراسة تاريخية وأثرية خلال العهد الإسلامي. تيزي وزو: دار الأمل للطباغة والنشر والتوزيع.
Daumas, M. et M. Fabar. 1847. La Grande Kabylie : études historiques. Paris: Hachette.
Murcía, Carles. 2011. Que sait-on de la langue des Maures? Distribution géographique et situation sociolinguistique des langues en Afrique Proconsulaire. In C. Ruiz Darasse et E. R. Luján (éd.) Contacts linguistiques dans l’Occident méditerranéen antique. Madrid: Collection de la Casa de Velázquez (126), pp. 103-126.