Accessibility is something we care a lot about on the Hangouts team. The Hangout Captions app, for example, enables live transcription services for the deaf and hard of hearing (http://goo.gl/4RujF). And "Take the Floor" makes it easier for sign language speakers to do a Hangout together (http://goo.gl/chyKS). Today we're rolling out two accessibility improvements in Hangouts - a Sign Language Interpreter app, and a fuller set of keyboard shortcuts.
1) Using the Sign Language Interpreter app, deaf or hard of hearing users who prefer sign language can invite interpreters to speak and sign for them during a Hangout. They'll always see their interpreter at the top right of the window, and they'll become the focus of the Hangout whenever their interpreter speaks for them. You can install the app using this link: https://plus.google.com/hangouts/_?gid=532733437531.
2) Keyboard shortcuts are also available in Hangouts -- great for people who can't or don't want to use a mouse during the video chat. For example: muting your microphone is now as simple as Ctrl+D (PC) or Command+D (Mac), and you can start chatting with Ctrl+B (PC) or Command+B (Mac). To view the full list of keyboard shortcuts just type '?' while in a Hangout, or visit this page:support.google.com/plus/bin/answer.py?answer=2752487.
Both features are rolling out gradually, so let us know what you think once you've taken them for a spin!