Heres my take on the whole thing.
I have worked it out from the following premises:
1. Lizardmen see themselves as the firstborn of the gods.
It is their entire identity to live up to this role, and do as they have been born to do.
2. Lizardmen are spawned together in groups.
It would be natural for them to observe that they are "brothers" or "siblings", and refer to others as such.
At the same time the reference would end up being something as a title.
Until you have proven yourself you will be refered to as "a brother", but when you stand out of the group you were born with, you become alone and thus is refereed to as a "one" (see below).
You are a brother when you are one of many, you are a "one" when you are a rarity.
3. The old world have little if no idea about all of this. Their naming of the lizardmen would be based entirely on observations, and
should depict a clear lack of understanding of the actual circumstances.
Current - In Own tongue - in Tongue of man
Lizardmen - The Firstborn - Saurian Dynasty
(As viewed from the outside, Slann would be seen as a ruling family)
Slann - First Child - Sovereign Mage Lord
Oldblood - Ancient One - Saurian Ancient
Scar Veteran - Scarred One - Saurian Veteran
Skink Priest - Vessel of wills - Crest Priest
Skink Cheif - Brave one - Crest Brave
Saurus - War brother - Saurian Warriors
Temple Guard - Keeping Ones - Saurian High Guard
Skinks - Nimble brother - Crests
Kroxigor - Mighty Brother - Saurian Cleaver
Chameleon - Ones without (Crest, "shape") - Stalkers
Skinks
Carnosaur - Hunter King - (Apex) Carnorexia
(Badly translates to Appetite for meat)
Stegadon - Horned Mountain - Triceradon
Cold Ones - Bad-tempered war-fang - Irasaur (Irasuar Riders)
("Ira" means anger or wrath, and circumstances will that it fits pretty good with their new rules)
Bastiladon - Tailed Mountain - Fortress Beast
Terradon - Wind swimmer - Tenuisaur
(Tenuis = "Slender" or "Delicate"
Ripperdactyl - Fanged hurricane - Winged Rippers
Troglodon - Pale Cave terror - Orcusaur
(Orcus = "Underworld" and "Death"
Salamander - Vulcano stomach - Scorch Spewer
Razordon - Spearback - Spike thruster
Dread Saurian - Godmaw - Kaijusaurus
(this is a joke.....couldnt come up with anything)