Ever since 2011, virtual voice assistants have been all the rage. First, Apple's (AAPL 0.51%) Siri came out to much fanfare, followed by Google (GOOGL 1.42%) Now. Nuance Communications (NUAN), which powers the voice recognition behind Siri, even has its own Nina assistant. Amazon.com (AMZN 1.49%) has now reportedly purchased Evi, a mobile assistant app for iOS and Android. The e-tailer has also separately acquired several small voice recognition companies over the years.

In the video below, Fool contributor Evan Niu, CFA, discusses how Amazon could be looking to integrate a new voice assistant into future Kindle Fires or possible a Kindle Phone.