Dragon's Tongue

The language known as the Dragon's Tongue is an ancient language spoken by academics and heroes and so-called "dragon hunters", and that imitates the sounds of dragons. It follows the belief that dragons are sentient beings with an intricate language similar to other sentient languages with rules of grammar, syntax, and more. Scholars spent centuries trying to decipher the growls and hums and chirps and roars heard by dragons, trying to establish patterns and distinguish dialects, writing book after book in strange symbols and imitating sounds in drawings, and adding the vibrations of thunderous pounces into letters with curvy lines.
When not asking the scholars and elders who firmly believe that this language can be used to speak with dragons — after all, many who try fail to convince a dragon of their good intentions (meaning that they are eaten before they get out) or they are stared at by a confused dragon who clearly does not speak their dialect and ultimately leaves them be, deciding that they're too much trouble to be worth the kill.
When asking outsiders who have not been affected by dragon-fever, so to speak, most believe that the Dragon's Tongue is, to put it mildlly, utter bullshit. In fact, it is their conviction (which is very plausible, asking the dragons), that dragons don't understand a single word of the so-called Dragon's Tongue, but that the amount of people surviving after "speaking" with a dragon as opposed to crossing it without knowledge of the language is more likely down to the sheer bafflement a dragon must feel when the small two-legged minions get all puffed up and attempt to roar and growl at a monster sometimes ten times their size or more. The little toothpick they carry on their belt as a sword is not enough to deter a dragon either, but maybe out of respect, a dragon will write them and their flundering attempts off as a child playing, maybe reminding them of their young, and they decide to let the fussy little creatures go who try so hard to play dragon.