How do Dragons communicate?

On cellular devices in English

AnotherIt all depends upon the Dragon, some Dragons are said to talk via telepathy, some just outright in Latin or a language of their own, and some write.

In The Wizard of EarthSea the Dragons had a language of their own. Wizards learned to use this language and by it had command over elements and other elemental forces. Curiously, a wizard (human) was incapable of lying in this language but a Dragon had no such a problem.