Not much input but this is something I've been thinking of too with my fc's growing interest in some dragon plot lines. The best idea i could suggest is to go over all the in game dragon names and just take notes of them and work from there. I mean some of the more lore heavy dragons have well known names (while they may very well have a dragonspeak name too) and others are named like the little whelpling. That or maybe the above post is right in that some were given names later while others were not.
Wiki:Â Lorraine Dunois
Being heavily revamped/reworked atm - sorry
