I'm sorry, but that is not a believable stat. You mean to tell me close to 1/10 of the planet is deaf and speaks ASL and doesn't read a written language?
I'm all for the project. I'm 100% in favor of increasing accessibility. I just don't believe that stat.
Are you sure it isn't 700k? That'd be more reasonable considering Wikipedia says a 1972 survey estimated the signing population as between 250k and 500k.
700M is simply ludicrous. Even if that's only taken as the number of ASL signers, that would still make ASL the third largest language in the world, ahead of Hindi and Spanish.
While the number is clearly far too large even taking into account what I'm about to say, I think someone doesn't have to not read any written language to be excluded. For many ASL speakers, ASL, not English, is their native language. Although I read French passably, I would consider subtitles available only in French, and not in English, to be serving my needs poorly; and I think the same can be said of an ASL speaker asked to "make do" with English-language subtitles.
The rate is 5%.
OP should clean up that marketing pitch. I think it’s a good service that doesn’t have to be sold by shaming the potential customer.
And they don't all use ASL, either. Not all deaf people rely on sign language, especially if they became deaf later in life, and there are numerous other sign languages used outside the US which aren't mutually intelligible with ASL.
https://earthweb.com/sign-language-users/
"Roughly 70 million hearing-impaired and deaf people all over the globe use sign language to communicate."
so presumably not just ASL. In any case, this is probably a sorely needed service, if there are robust production pipelines for subtitling and dubbing in other written languages but not for sign languages.