Ralph von Wau Wau is a German Shepherd with mutated genes which resulted in human-level intelligence. By coincidence he was also surgically altered by an experimental veterinarian named Malion to give him a voice box capable of human speech.
Ralph often speaks in a fake German accent in varying strengths. He drops his accent nearly completely when angry.
Ralph's mutated genes also must have resulted in an increased life span since "Dog Day Evening" was written in 1977 and he is still alive and well in "Callahan's Con" more than 20 years later. Pixel's longevity is also unexplained, but his intelligence and ability to teleport suggest he also is a mutant.