The dragon most definitely had a speaking part. In fact his dialogue with Bilbo is actually quite funny in places.
I don't remember the one armed 'goblin' (Tolkein didn't start calling them orcs until the Rings trilogy) either. He might be in the appendices to Rings, or just one tale in the many songs or family tree references featured throughout the books. I don't think he was technically a Hobbit character though. The warg riders that attacked the party weren't individualized. Mostly they just sang sadistically:
Fifteen birds in five firtrees,
their feathers were fanned in a fiery breeze!
But, funny little birds, they had no wings!
O what shall we do with the funny little things?