Chatbot training
Natural language understanding was the stuff of science fiction for a long time. In science fiction, you can just chat with your starship's computer to get useful and relevant information about the recent alien invasion, without pressing any button. This scenario was exploited by authors and filmmakers for decades, but in real life, such interactions with computers started to become a reality only recently. You still can't talk to your starship, but you can, at least, switch your toaster on and off without pushing buttons, which is undoubtedly a major step forward!
The reason why it took computers so long to understand language is simply due to the complexity of language itself. Even in trivial scenarios—like saying, "Toaster, switch on!"—you can imagine several ways to formulate your command, and it's usually very hard to capture all those ways and corner cases in advance using normal computer programming techniques. Unfortunately...
