Has someone indicated that something you wrote is such that "the language is understood", and definitely understood, but only in the sense that each individual word is in the critic's vocabulary and, from the critic's point of view, what you wrote makes no sense given how the words have been organized?
To me that's a strange notion, partly because one might need to specify whether somebody heard what you wrote, read what you wrote, or both. For example, without context, there's no way to distinguish between the verb "construct" and the noun "construct" in written English, but there is a difference (at least among people who are completely fluent in English) between the spoken verb "construct" and the spoken noun "construct". For example, without context, there's no way to distinguish between the spoken word "for" and the spoken word "four", but it's easy to distinguish between those written words.
Since I am not all-knowing, and some others who have access to this message aren't all-knowing, it might be interesting to observe that somebody could hear a spoken word and not know that the spoken word, without context, is ambiguous. For example, the word "intention" might be in the person's vocabulary, but the word "intension" might not.
Below is a link to a thread (not on DU) about the words "intention" and "intension."
http://forum.wordreference.com/showthread.php?t=82726More generally, I get the impression that we the non-all-knowing folks aren't in a position to claim to know all of the vocabulary in a message if the way the words of the message have been organized makes no sense. After all, we would have to investigate to see whether or not any spoken word that we do recognize has, in addition to a meaning that we know of, an alternative meaning that we aren't familiar with. We would have to investigate to see whether or not any written word that we do recognize has, in addition to a meaning that we know of, an alternative meaning that we aren't familiar with.