Ɣur F. de Saussure, tasnilest d tussna izerrwen tutlayt. Temgarad ɣef tussniwin d taɣulin-nniḍen ilan assaɣ d uzraw n tutlayt (am tesnaḍrist, tajerrumt d tesnilest timserwest) deg usentel n uzraw akked tesnarrayt. Tasnilest, ur terzi ara kan tutlayin yuran neɣ tutlayin n tɣermiwin timeqqranin; tzerrew akk tutlayin n umaḍal, i bɣunt ilint talɣiwin-nsent : d tutlayin yeddren neɣ d tid yemmuten (ma ǧǧant-d iḍrisen yuran), d tutlayin timawin neɣ d tid yuran, tid ilan aẓayer asertan inmetti neɣ war aẓayer, atg.