Transcendence and Revelation Since


God transcends all humans and all their artefacts; and
almost all revelation occurs within human languages, which are in a definite sense human artefacts;
isn't it the case that Divine Revelation must necessarily be “incomplete” to some extent in order to be carried by a limited medium such as the human language?


edited as per suggestions
If God, were only transcendant, perhaps there would be something to what you're saying, But Orthodox (in the wider sense of the word) Christian teaching is that God is both transcendant (we can't know Him fully) and Immanent - he is 'close' and fully able to communicate to his creatures clearly (at least to their level of comprehension). 

Orthodox Christianity would further qualify your second premise as God initially gave language to man when he created him in his image (cf. Genesis 1:26-29).  Subsequently, human languages were confused and multiplied by God's direct agency as well (cf. Genesis 11:1-9), so there is a sense that language's are not 'purely' human artifacts at all.  It is true, that since Babel, languages have multiplied further with cross-pollinations and evolutions - this process may have lead to further confusion between humans, but it is not a limiting factor in God communicating what He chooses to communicate to mankind - as he is both omniscient and omnipotent.

With regard to revelation, we can not know everything there is to know about God with our mortal limitations, but what God chooses to reveal to mankind, He also has the capacity to make clear - as He is the Master of all language. (cf. Acts 2)