Slave Ship by Fredrick Pohl [1957 PAPERBACK]

FIRST PAPERBACK PRINTING [1957] BALLANTINE BOOKS

First they cracked the codes. The big electronic calculators that handled math codes, production lines, found it simple to decipher the small but racy vocabularies of the animals. 

Then man had achieved the age-old dream: He could respond when his dog struggled to tell us something, and he could tell that foolish sheep that if he didn't act right he'd be mutton; and, being a man, he could create the wildest, craziest secret weapon for the war that's man's heritage but not that of the new, now-articulate minorities.