http://composition.al/blog/2014/05/31/your-next-conference-should-have-real-...
I went to this conference and it worked out really well. As the Computer-Assisted Realtime Transcription (CART) captioner writes at http://stenoknight.com/demo.html :
When an event needs to be made inclusive, projecting the CART display for the benefit of the entire room can be the best way to provide universal access for Deaf, late deafened, and hard of hearing people, as well as people who might have some degree of hearing loss but who don’t self-identify as hard of hearing or deaf. CART is also useful for English language learners and people with dyslexia, auditory processing disorder, or ADHD. When the CART display is available to every audience member, no one has to feel singled out or as if they’re demanding special privileges. Everyone benefits.
Live transcriptionists can work onsite, or can work remotely via an audio feed and then stream the text remotely onto a screen at the venue. And you can often use the resulting transcript and - with trivial editing - put it up within days of the event.
This particular conference (!!Con) was able to get a sponsor to pay specifically for the captioning. I'd like to suggest that Wikimanias from 2016 onward also try to do this, at least for the plenary sessions, and perhaps additionally for sessions where we especially want to welcome Deaf participants and/or people with less fluent English.