Chapter 14 of Joyce's Ulysses, The Oxen of the Sun, frequently changes writing styles as it unfolds. Joyce was attempting to mimic the development of the English language, from its Latin roots through to modern-day street slang.
Many of these passages are extremely difficult to understand. Here's an example modelled on the work of early Roman historians:
Universally that person's acumen is esteemed very little perceptive concerning whatsoever matters are being held as most profitable by mortals with sapience endowed to be studied who is ignorant of that which the most in doctrine erudite and certainly by reason of that in them high mind's ornament deserving of veneration constantly maintain when by general consent they affirm that other circumstances being equal by no exterior splendour is the prosperity of a nation more efficaciously asserted than by the measure of how far forward may have progressed the tribute of its solicitude for that proliferent continuance which of evils the original if it be absent when fortunately present constitutes the certain sign of omnipollent nature's incorrupted benefaction.
Here's another, which mimics the work of Aelfric, a 10th century Anglo-Saxon writer:
Before born babe bliss had. Within womb won he worship. Whatever in that one case done commodiously done was. A couch by midwives attended with wholesome food reposeful cleanest swaddles as though forthbringing were now done and by wise foresight set: but to this no less of what drugs there is need and surgical implements which are pertaining to her case not omitting aspect of all very distracting spectacles in various latitudes by our terrestrial orb offered together with images, divine and human, the cogitation of which by sejunct females is to tumescence conducive or eases issue in the high sunbright wellbuilt fair home of mothers when, ostensibly far gone and reproductitive, it is come by her thereto to lie in, her term up.
My question is this: not being familiar with the overwhelming majority of historical styles employed, it is not clear to me whether or not the incomprehensibility of the text is a consequence of the style it's mimicking? Or to put it another way, could Joyce have attempted this literary history lesson while leaving the text easier for the reader to follow?