S-kyuu Guild wo Tsuihousareta kedo, Jitsu wa Ore dake Dragon no Kotoba ga Wakaru no de, Kidzuita Toki ni wa Ryuu Kishi no Chouten wo Kiwametemashita.…

[Miserys_End]

Isn't our MC here only one capable of talking&understanding them?
To rest he could just be making shit up.

MC is the only one that can directly talk to any dragon, but that's not to say that dragons like Chris have no method for communicating with humans. It's just been lost to time.