Natural Language Processing allows sentiment analysis in finance for example. Provided with just the text of an earnings call. We can give you feedback programmatically regarding the overall sentiment score of the call. Using Python's NLTK library we will demonstrate an example. (Please install twython as well in order to avoid getting warnings or disregard them). More about NLTK and Python can be found here : Bird, Steven, Edward Loper and Ewan Klein (2009), Natural Language Processing with Python. O’Reilly Media Inc.
This is what we get as a result:
compound: 0.765, neg: 0.0, neu: 0.815, pos: 0.185
Text to speech example