In some ways, Martel has his cake and eats it too. He's written a book with unpretentious, casual language that's also capable of stunning lyricism. You'll be moseying along, listening to Pi tell it like it is, and BAM! there's a moment of intense beauty. It's like going outside to get the mail at the end of the day and seeing a gorgeous, dripping sunset. It's a little unsettling:
Killing it was no problem. I would have spared myself the trouble – after all, it was for Richard Parker and he would have dispatched it with expert ease – but for the hook that was imbedded in its mouth. I exulted at having a dorado at the end of my line – I would be less keen if it were a tiger. I went about the job in a direct way. I took the hatchet in both my hands and vigorously beat fish on the head with the hammerhead (I still didn't have the stomach to use the sharp edge). The dorado did the most extraordinary thing as it died: it began to flash all kinds of colours in rapid succession. Blue, green, red, gold and violet flickered and shimmered neon-like on the surface as it struggled. I felt like I was beating a rainbow to death. (2.61.31)
Notice the echoes of well-worn phrases, at least early on, in this passage: "spared myself the trouble," "dispatched it with expert ease," "I went about the job," "I still didn't have the stomach," and so forth (2.61.31). Next thing you know Martel sucker punches you with some pretty poetic language: "I felt like I was beating a rainbow to death." Moral of the story: watch out, because when you least expect it, Martel will get all pretty on you.
Also, Martel also uses surprisingly little dialogue, excepting the extended conversations near the end of the novel. Probably because Pi doesn't have anyone to talk to for about 150 pages.