The vaudeville stage welcomed plenty of animal acts, but Don the Talking Dog was the tops in his time. Don was a well-known performer in his native Germany, where he displayed his ability to speak several German words. The dog show evoked curiosity in the US, and there was plenty of hype when Don finally crossed the Atlantic in 1912. Newspapers followed his every move, and crowds formed everywhere he performed.
With a vocabulary that ultimately reached eight words—all in German—Don had garnered attention in the United States as early as 1910, with breathless newspaper reports from Europe. According to some accounts, his first word was haben(“have” in English), followed by “Don,” kuchen(“cake”), and hunger (same word in English and German).
Theoretically, this allowed him to form the useful sentence: Don hunger, have cake—although most accounts say he typically spoke just one word at a time, and only when prompted by questions. He later added ja and nein (“yes” and “no”), as well as ruhe (“quiet” or “rest”) and “Haberland” (the name of his owner).
Don stayed in the US for two years, during which time he was treated as royalty, and made plenty of money, both from shows and from endorsing Milk-Bone dog biscuits. Scientists were interested in Don, too, and you can read about their conclusions at Smithsonian.