Cleon
Legend
That works on the languages. Tactics are also good!
Updating Pearl the Moon Dragon Working Draft.
The other Colossal unique dragons I checked in the CC are around 120+ ft long and 220+ tons, except for Ahi, who's rather puny for his size category. One is 170 feet and 350 tons. Want to go with something like 140 ft and 260 tons?
Well there are 2E AD&D versions of Tiamat that are 360 feet (Polyhedron #36, 1992) or 500 feet (DMGR4, 1992) long, and she has kids of the 140 ft. size you suggest (i.e. An-Ur).
Besides, Pearl is a Chaotic shapechanging dragon, so might be whatever size she wants to be.
How about:
Pearl's natural pearlescent dragon form is mutable and can change size and shape at will as described under her Alternative Form ability. Her normal Colossal size can range from 100 to 300 feet in length (including tail) and weighs 50 to 1,000 tons.
Alternate Form (Su): Pearl can assume any animal or humanoid form of Huge size or smaller as a standard action. She can also assume the form of any of the chaotic dragon varieties she rules over of any age category from wyrmling to great wyrm. The Moon Dragon can remain in an alternate form until she chooses to assume a new one or return to her natural form.
Her natural form can be any size between Tiny and her normal size of Colossal and can assume the shape but not the coloration of any chaotic dragon, including wingless and legless species (she can still fly magically in wingless forms). Pearl can resize and reshape her natural form as a free action once per round.