De acordo com o Apêndice F do O Senhor dos Anéis , eles não "grunham e rugem", eles são capazes de falar; mas eles não falam na Língua Comum ou em qualquer outro dos povos da Terra-média:
Trolls they were, but filled with the evil will of their master: a fell race, strong, agile, fierce and cunning, but harder than stone. Unlike the older race of the Twilight they could endure the Sun, so long as the will of Sauron held sway over them. They spoke little, and the only tongue that they knew was the Black Speech of Barad-dûr.