I can understand the nature of the question in terms of comparing Benjamin to Squealer. Squealer talks so much that it might drown out all the other animals. Yet, I do think that Benjamin does talk. By his own nature, Benjamin is cynical and less predisposed to speak in terms that would compel his speech to be consistent. He is more of the mindset that he rarely speaks. Yet, he does speak in cryptic and, sometimes, quite powerful terms. This is seen in the third chapter of the work. While the other animals are buzzing with activity in the wake of the revolution and the change of ownership, Benjamin offers a statement that might actually foreshadow how the narrative will unfold:
Donkeys live a long time. None of you have ever seen a dead donkey.
The idea implicit in his words at this point is that the more things change, the more they stay the same and donkeys like Benjamin bear witness to this. The other critical moment in which Benjamin speaks would have to be at the end when his friend, Boxer, is being taken away from the farm as a result of his injury. It is at this point where Benjamin is the most intense in both his mannerisms and his speech:
Quick, quick...Come at once! They're taking Boxer away!
This is the first time we see Benjamin is his most intense and stirred to the most heights of action. This is only eclipsed by his realization of what will happen to his friend:
Alfred Simmonds, Horse Slaughterer and Glue Boiler, Willingdon. Dealer in Hides and Bone-Meal. Kennels Supplied.' Do you not understand what that means? They are taking Boxer to the knacker's!
At these moments, Boxer does speak for more than himself, but for the condition of the animals on the farm.