A state in which no language is used, yet the entire essence is understood completely is called the Para Vaani.
After death, when a person leaves his body, he also drops his ability to communicate using language. At that state, he simply observes all that happens, and by observation he gains knowledge. This is called Pashyanti (derived from the Sanskrit word ‘Pashya’ meaning to see or observe).
The Madhyama mode of speech is in-between the states of Para and Pashyanti.
Many times it happens that someone is speaking in a language that you do not know, yet you are able to understand what they are trying to say. Madhyama is such a state. For example, when the child is in the mother’s womb, neither has the child seen the mother, and nor has the mother seen the child. Yet they understand each other completely. There is no exchange of language in that state, then too, communication happens that is beyond language. This is Madhyama.
That is why this entire creation is called as the Hiranyagarbha (meaning the Golden Egg or Golden Womb). We are all present inside this Cosmic Womb and do not know what exists outside it.
Just like how the mother knows the child within her womb but the child does not know the mother; in the same way God knows us yet we do not know Him. That is why He is referred to as Agyeya (that which is ever-present but is unknown). You can never know the Divine, but you can experience it. And how can you experience it? By reposing in yourself.
So Para Vaani is that speech in which no language is used, and it is also beyond feelings. In Pashyanti we communicate using our feelings also.
When we go into deeper levels of Consciousness, every sense organ of our body becomes capable of performing all functions. That means the functions of all the five senses happen through one organ.
So in such a state, by a single touch you are able to feel, see, taste and also gain complete knowledge about the object.
So every organ becomes capable of performing all the functions of the five senses (see, smell, taste, hear, and feel). So when the Panchendriya (five senses) dissolve and become one (sense organ), then that state is the state of Para-Chetna (pure Consciousness). That is the speech of Para Vaani.
That is why it is said, ‘Jaanat tum hi tum hi ho jaaye’ (when the knower, knowledge and the known all become One). That is why we say, one who is deeply devoted to the Lord becomes the Lord himself.
Similarly, one who has attained the knowledge of the Brahman becomes the Brahman. In such a state, the lover, the beloved and the love are not separate from one another. They all dissolve and become one. This is the state of Para Vaani.
When you think of language, then there has to be one who speaks and another who listens. Two are needed for this (meaning a sense of duality). This is where you need Vaikhari. Vaikhari means the diversity that is present all around you. That is why there are so many languages in the world, and not just one. But there is only one Para Vaani, and everything is contained in that.
In Para Vaani, even before a word is formed you have instantly understood the meaning. So words are not needed at all.
All this appears very technical to understand. So when you have a scientific outlook, then it is easy to understand.