No Dark Place
Draconic is divided into tiers, each tier marked both by grammatical characteristics and by pragmatic rules. In reptilian societies, including kobolds, yuan-ti, khaasta, and of course dragons, speech is governed by caste and station. The lowest form of Draconic (rit’Sorrukh) is spoken by kobolds and other reptilian humanoids whom the dragons regard as too inconsequential to use better. Formal Draconic (so’Sorrukh) is a more decorous language, and is usually the tier learned by mortals. When wizards incant the verbal components to their spells, they are most often speaking so’Sorrukh.
The dragons themselves speak ka’Sorrukh, which they insist is the pure form which predates its debasement by lesser creatures. ka’Sorrukh is a vast and highly structured language, with words sometimes so lengthy that they cannot be spoken by humans in a single breath. Although it would likely be taken as an insult by a living dragon, it has been postulated that ka’Sorrukh is simply a more mature understanding of the same language as so’Sorrukh, simply altered over the incredibly long lifespans of the dragons who speak it.
Most formal arcane methodologies have adopted Draconic as the script used in tomes, scrolls, spellbooks, and other magical writings. The origins of this practice go back nearly as far as the recorded history of mortal wizardry, with the magic learned from ancient dragons themselves.