Ulysses (and even more so Finnegan's wake) is not written in a natural language. It is a constructed artificial language. Many of Shakespeare's works are also written in a constructed language because of their need for rhyme and rhythm, albeit closer to the natural language of his time. I've also noted that rhymed text, even if otherwise using natural syntax, is harder for me to follow as my brain tends to get lulled by the rhyme itself and stops paying attention to the content, it's just trying to predict the pattern.

Now that said, the idea of comparing programming languages with natural languages or even constructed languages seems very strange to me. Natural languages are tools for thought, expression and communication. Programming languages are tools for, well, programming. Even the relationship between the grammar of a PL and the grammar of a human language is distant (we often intuitively think of identifiers as similar to nouns and verbs in human languages, but in fact all identifiers are equivalent to proper nouns in human languages, and the actual equivalents of nouns and verbs are stuff like block openers, significant white space, function application, maybe the keywords).

It is a well-known fact already that humans can only naturally learn human languages, which have a specific kind of grammar. Even some clumsy attempts at standardizing human language end up introducing un-natural grammar that children can't pick up until later in school when it is drilled into them. It would have been truly surprising to find out that we can use our natural language capacity for something as alien as a PL.