The Frankish nobility would have been a minority in a land which was majority Romance speaking (Gaulish having unfortunately died out out by then). And at a cer

The Frankish nobility would have been a minority in a land which was majority Romance speaking (Gaulish having unfortunately died out out by then). And at a certain point they were very interested in emulating and continuing the lineage of the western Roman empire, explicitly taking up late Roman styles and practices. Adopting Latin and Gallo-Romance speech would be just part of this. Happened with the Goths in Spain as well. It's interesting to compare to Anglo-Saxon England where this did not happen and the native Brittonic speech as well as late Romano-British Latin was wiped out.