The company previously offered text transcripts to accompany CNN news updates, but they were limited to the news presenter's script.
The new service offers live subtitles for content including news headlines, current events and entertainment. The service will be expanded in the future to cover other video content.
"Online captioning is a central accessibility issue for the deaf and hard-of-hearing communities and we are excited to be at the forefront of the movement," said Tom Wlodkowski, director of accessibility at AOL.
"Key to our progress has been our collaboration with WGBH and support from content partners such as CNN. We look forward to working with additional content providers to expand the availability of captioned video content across the AOL network."
The subtitles, or 'closed captioning' as they are referred to in the US, appear below the video as it's played. Users can access them by clicking the 'CC' button in AOL's media player.
"Offering consumers a complete and comprehensive online video experience is one of AOL's top priorities and a big part of that is providing a top-notch playback experience," said Kevin Conroy, executive vice president at AOL.
"Closed captioning unlocks a new world for millions of consumers who, until now, have been unable to fully experience viewing videos online."
More information can be found at AOL Accessibility.
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