We have a language for describing common human experience. When I say the words "happy", or "sad", or "peaceful", or "suspicious", you feel like you know exactly what that feels like without ever having been inside my head. By virtue of being human, you know what these feel like.
Religious experience is different from that. For starters, not everyone even has religious experiences. Some have them so rarely that they count them as anomalous malfunctions of the otherwise smoothly operating mind. Others might have them but not recognize them as such. So you may say, there aren't words for that experience because it is uncommon. It is unclear to some extent what experience the terms "religious experience" might refer to, or it might refer to many different things.
It is much more than that, however. No matter how much religious experience is part of your life, every time it is to some extent new. When something is completely new, there is no possibility that language already exists for it, since the event is prior to finding words for the event. An event has to be common, identifiable and reproducible, before there can be words for it.
Think about the most significant conversation you ever had, with the most interesting person you ever met. Did you feel like new worlds were continually unfolding before you? Interacting with God is a continual unfolding, and unlike with people, there is never a point at which there is no more to unfold. The revelation constantly regenerates, it is always new. Even if the experience were to last an hour, a day, 100 years, or 1000 kalpas, it would be continually new, because its source is inexhaustible. It's source is also outside time, so it is not that it is new in time and later it would not be new. It is new inherently, although all religious experience shares its source and so they all have the same subject, as it were. But these are all words. The loved one looks into the eyes of his beloved, and time stops. How much more, when the beloved is God?
I often speak of the world as a trap we have to escape from, and so my focus is often on not coming back. Not reincarnating here. And I do think that is important, but how could we achieve that if not by experiencing God here and now? So the distinction between hereafter and here are not as absolute as we might think they are. We have to already be walking the path out of the World while we are in it, in order to keep walking it after.
