Computational linguistics

Computational Linguistics is a field of linguistics that deals with making computers understand human language. Some of the biggest sub-fields of computational linguistics are:
Speech recognition, which is a computer program that listens to people talk and writes down what they said
Speech synthesis, which is a computer program that takes writing and reads it out loud
Machine translation, which is a computer program that turns one language into a different one
Dialog Systems, which is a computer program that talks back-and-forth with a human to help them do something