The Sheep Look Up by John Brunner. Whilst it's a very highly rated environmental sci-fi novel I just couldn't get past the fragmented way in which it's told. Shame really as I've managed to persevere through some terrible books and I wouldn't say that it's terrible but I just can't get on with it.
I was the same with one of Iain Banks sci-fi books. It was written in such an odd style, rather than be told the main character had a certain accent it was written so you had to read it in their accent, which just made it slow and annoying.
Sounds like Feersum Endjinn? Yes, one of the viewpoints is written in a phonetic style. Loved the book though but you do need to read those sections carefully. If you've attempted Trainspotting then it's a doddle.
It's one of his standalones so the good news is that the rest of his sci-fis are much easier to read! I loved the ending of FE though, as well as the world he created (the enormous castle?).
Have you read Excession or Use of Weapons? For me, they were probably on a par with having to concentrate hard to follow all the threads. UoW made me want to re-read the entire book just as soon as I finished