There is a certain concord in angelic speech that is indescribable. This concord stems from the fact that the thoughts and affections that give rise to speech flow forth and spread out in keeping with heaven’s form, heaven’s form being what determines how everyone there associates and communicates. (See Sections 200–212, on the way heaven’s form determines how angels associate and the flow of their thoughts and affections.)
The same kind of speech we find in the spiritual world is innate in all of us, but in the deeper part of our intellect. However, since for us it does not come down into words that parallel our affections the way it does for angels, we are unaware that we possess it. Yet this is why we have access to the same language as spirits and angels when we arrive in the other life and know how to talk with them without being taught. But more on this below.
There is, as already noted, a single language for everyone in heaven; but it does vary, in that the language of wiser people is more profound and more full of shades of affections and specific concepts. The language of less wise individuals is less profound and not so full, and the language of simple people is still less profound, actually consisting of words that yield meaning only the way they do when we on earth talk with each other.
There is also a language of facial expressions that switch over to a sound modified by ideas, and a language in which images of heaven are combined with concepts and the concepts are presented visually. There is also a language of bodily movements responsive to affections and portraying the same things that their verbal expressions do. There is a language of shared affections and of shared thoughts; there is a thunderous language; and there are other languages as well.
The language of evil and hellish spirits is much the same, because it too stems from their affections, but it comes from evil affections and their foul concepts, which are utterly repugnant to angels. This means that the languages of hell are opposite to the languages of heaven. Evil people cannot stand angelic speech, and angels cannot stand hellish speech. To angels, hellish speech is like a rank odor that assaults the nostrils.
The language of hypocrites—people who can imitate angels of light—is like that of angels as far as its words are concerned, but exactly opposite in respect to its affections and their individual thoughts. So when the inner quality of their speech is perceived, as it is by wise angels, it sounds like a grinding of teeth and strikes horror into them.
from Heaven and Hell, Sections 242-245