Natural languages are human languages such as English. Making computers understand English allows non-programmers to use them with little training. Applications in limited areas (such as access to data bases) are easy.
(askr '(where can i get ice cream in berkeley))
Natural Language Generation:
Easier than NL understanding. Can be an inexpensive output device.
Machine Translation:
Usable translation of text is available now. Important for organizations that operate in many countries.
In a not too far future develops for eleven-year old David in a research lab the first intelligent robot with human feelings in the shape. But its "foster parents" are overtaxed with the artificial spare child and suspend it. Posed on itself alone David tries to fathom its origin and the secret of its existence.