Because the list of words the speech recognition system has to understand reliably is extremely limited. There are probably what, 200-300 words the system has t

Because the list of words the speech recognition system has to understand reliably is extremely limited. There are probably what, 200-300 words the system has to understand for a pizza service? It's fairly simple to fine-tune speech recognition if you have a small dictionary of keywords you've given the engine extra training on. A pizza demo is perfect because it appears to be non-trivial, but I assume the engine has been fine-tuned a lot specifically for the demo. The interesting aspects of speech recognition are in handling natural sentences from the entire language, rather than a subset that has been heavily tuned to weigh specific words as being more expected for a given domain.