Why is it difficult for modern experts to translate some parts of the Mayan language? The language is no longer spoken and is not used for writing.
The Maya often destroyed cities when they were battling for new territory.
The Spanish destroyed many of the artifacts with the keys to the Mayan language.
The reliefs the Maya used to document their language have been damaged by wind and rain.

In 911, a group of vikings lead by rollo besieged paris and chartres. after a victory near chartres on 26 august, charles decided to negotiate with rollo. the talks were led by hervé, the archbishop of reims. this resulted in the treaty of saint-clair-sur-epte, which granted rollo and his soldiers all the land between the river epte and the sea. it also granted him brittany, "for his livelihood". at the time, brittany was an independent land which france had not been able to conquer. in exchange, rollo promised the king his loyalty and military assistance when needed. also rollo also agreed to be baptised and to marry gisela, the king's daughter. the territory given rollo is about the same as upper normandy. this would grow to become normandy under rollo's descendants. - wikepedia