Apple Siri

Siri, or Speech Interpretation and Recognition Interface, is an intelligent personal assistant from the American company Apple Inc. The users interact with Siri via a natural language interface. Siri is able to search for data and answer questions based only on a vocal input. The underlying algorithms learn user's habits and personal language and better itself in order to deliver more individualized results.

http://www.macworld.co.uk/feature/iosapps/complete-guide-siri-ios-features-commands-questions-voices-ios-9-apple-music-proactive-3495151/

http://www.huffingtonpost.com/2013/01/22/siri-do-engine-apple-iphone_n_2499165.html