This paper deals with the derivation of the preterite sdm=f in Late Egyptian. The preterite sdm=f expresses an action which has been completed in the past or in thepresent perfect. it function as indicative . verbal formin the Ancient Egyptian Language. There are different points of view as to the derivation of the preterite sdm=f. Some of them attempt to connet between the preterite sdm=f and the historical perfect sdm=f while others connected between preterite sdm=f and the present perfect iw sdm.n=f. They present different stages of Ancient Egyptian Lanuage and the development of the Egyptian Lanuage from Old Egyptian until coptic. content: 0.Hypothesis 1.Introduction 2. Historical development of the preterite sdm=f The derivation of Late Egyptian preterite sdm=f 3.1 LEg preterite sdm=f < OEg historical perfect sdm=f 3.2 LEg preterite sdm=f < MEg present perfect iw sdm.n=f 4.The Inflection of the 3ae-inf and anomalous verbs in perfect 5. The counterpart's features of preterite sdm=f and iw/sdm.n=f