Original sentence: Franconian is a linguistic marker for a number of West Germanic languages and dialects spoken in the former core of the Frankish Empire: the Low Countries (The Netherlands, Belgium and Luxembourg) and western Germany (around Aachen, Cologne and Trier).Linguists doubt whether there really is a Franconian linguistic family as no proof exists that the present Franconian languages and dialects historically developed from a common ancestor language.Low Frankish dialects and languages (via Old Dutch), for instance, are commonly accepted to be a descendant of Old Frankish, the proposed common ancestor and language of the Franks, while West Central German and the Upper German transition dialects might just have been heavily influenced by it rather than being its direct descendant
Edited sentence: Franconian is a linguistic marker for a number of West Germanic languages and dialects spoken in the former core of the Frankish Empire: the Low Countries (The Netherlands, Belgium and Luxembourg) and western Germany (around Aachen, Cologne and Trier) , descended from the Old Frankish language