The Google-owned company said this use of speech recognition technology is perhaps the biggest experiment of this kind online. Previously captions were just a small amount of content. It also said that, at first the feature is applied to English language videos, and other languages will be included in the coming months.

Google engineer Mike Cohen said that technology behind speech recognition had taken up for nearly 50 years, and had lastly become good to be used on a large scale. The project team emphasized that the product is not perfect.

In one presentation, software engineer Ken Harrenstien said “It is not a complete solution but it is a step on the way to the real solution,”

Mr Harrenstien worked on the project for five years and he said the launch of this feature for deaf people was a big deal personally.