Ma yella nuɣal ɣer wayen yeɛnan akud n tsiwelt deg ungal-agi « Leɣruṛ n ṭṭmeɛ », nufa-d amsawal mi ara d-yettales ineḍruyen n teḥkayt, yettuɣal ɣer deffir, tettili-d tiremt n tsiwelt mbaɛd taḥkayt (ultérieure) acku tuget n yineḍruyen ɛeddan, iɛawed isawel-iten-id. Syin akkin tasiwelt yella wanda i tedda d taḥkayt (simultanée), axatar iḥekku-d deg lawan ideg d-yella, tikwal texleḍ tiremt (intercalée), acku isawel-d aneḍru iɛeddan d win i d-iteddun maca tiremtagi ur teṭṭuqet ara deg ungal-agi.