Demons are not able to co-habitate with a good being. If the glass is full of goodness there is no room for evil. They often will flee at the presence of a saint or holy person.They speak verbally at times from the incubus -usually in common language. Jesus spoke to the possessed and they spoke back in a common language. They then left to inhabit swine nearby. They will try to instill fear in the ignorant but are afraid of those with spiritual knowledge. They are fallen angels and stripped of any power, can only use deception.The budha was said to have encountered demons just before enlightenment. He touched the earth to ground himself, his knowledge terrified them and they fled. I guess all cultures have different interpretation of the experience. The earth nurtures us with food and goodness. Indians and Aboriginal people recognized the power in the earth also. God created the heavens and the earth , they both have a purpose. We can know God through nature or heavenly inspiration because they are both his creation. Like knowing an artist by his paintings or a poet by his words -saint eule

Consider the play by Naomi Iizuka entitled "Language of Angels". It does not answer the question directly... but, then again, the play itself has many leaves many questions unanswered. Humans lie for good reasons and bad. God does not speak directly with man...

http://www.LanguageOfAngels.org

The demons speak a demonic language, I have yet not been able to get a earthly name of it, but I have heard them speak it, and they have learned me some of the words too C: It's not like any human language at all, and is very hard for humans to speak, and impossible to say ALL the words. They also have a pretty sweet written language.

Angels speak Enochian young one. Demons have a language called dimoori sheol or language of the damned.
Speaking either of theses through a human vocal chord is frankly impossible. Demons have a set of sixty voices per demon whereas angels has seventy seven. There is no possible way to mimic or even comprehend either of these languages without having been possessed by either side. This is extremely dangerous so please do not try either of these

Celestial and Draconic.

I have been spoken to. It was only in a whisper, and the only word I could make out was "Devil". I asked the person what he said, because I couldn't make out the rest, and he couldn't remember saying anything.

Perhaps you are hung up on an immoral choice you made and the emotional guilt it is manifesting through your suggestive psyche? We don't always consciously register our emotions, they are scientifically and mentally complex.

Which language do the angles speak in the grave.

I am an ordained Reverend and from what I have learned, studying all religions, not just the popular ones, most believers in creationism communicate with their lord/lords by way of tongues or mental projection of images. This is often considered gibberish to those who witness it, but it is considered a language none-the-less. As for demons, you would have to ask my colleague. He goes by the name of Fizzle Exmortus, and has had limitless experience with negative entities often referred to as demons. Demons are actually younger than angels and lords/gods in the instance of existence. According to Rev. Exmortus, demons are not actually related to religion, but separate entities that are above humans in the supernatural sense, but lower than angels. He has studied the supernatural (yes, religion is considered supernatural) in depth and has been privy to many things that most people would shed their sanity if exposed to. It is life-altering, but that is the way of our order. Rev. Exmortus can be found on Facebook and Microsoft. Do not be fooled by his common place appearance. He is a Reverend, ordained by the same order as me. He just happens to avoid looking the part. Be warned. What we seek, we find. What we find, we fear. What we fear can then destroy us.

How so? (Sorry, don't mean to hijack the thread. You can start a new one if you wish Reverend, I'm just curious.)

It's no problem. The simple explanation is that Angels and Gods, as they are referred to by religion, existed before what are known as "demons". Demons are simply supernatural entities that feed off mischief, much like a bully emotionally feeds off the torment of others. Angels are Entities assigned by a creator/interferer (a God) to protect a region or being. Thus, the creators (Gods) made "angels" to protect other beings. "demons" are not created by said "gods", but a bi product of creations or evolutions of previous creations. Thus, it is likely that Gods and angels speak a language more ancient than demons.