8. Sound and speech interface

This type of interface allows the user to speak or type in their normal everyday language in order to interact with the computer.

For example, some applications such as speech recognition software accepts the spoken words and converts them into text on the computer. These applications have a much wider vocabularly than the dialogue interface.

An example of a natural language interface which makes use of written text is a 'chat bot'. This software mimics a conversation - you ask it questions and it will come back with a suitable comment for you.

This is the most technically challenging form of interface for the designers as it has to cope with different accents, dialects, slang, homonyms (bare or bear) etc.