Trolls . Troll has been used to translate the Sindarin Torog. In their beginning far back in the twilight of the Elder Days, these were creatures of dull and lumpish nature and had no more language than beasts. But Sauron had made use of them, teaching them what little they could learn, and increasing their wits with wickedness. Trolls therefore took such language as they could master from the Orcs; and in the Westlands the Stone-trolls spoke a debased form of the Common Speech.
...[Olog-Hai] spoke little, and the only tongue that they knew was the Black Speech of Barad-dûr.

(...)
But Orcs and Trolls spoke as they would, without love of words or things; and their language was actually more degraded and filthy than I have shown it I do not suppose that any will wish for a closer rendering, though models are easy to find. Much the same sort of talk can still be heard among the orc-minded; dreary and repetitive with hatred and contempt, too long removed from good to retain even verbal vigour, save in the ears of those to whom only the squalid sounds strong
- Appendix F