Since she can only squeak, I figured I’d play around with ways she can communicate with the player. Also a great perk for our deaf players.
Richard Lico of Polyarc Games, via Twitter

Sign language is rarely seen in games, but it is another valid means of communicating information to people who are deaf / hard of hearing.

However be aware that sign language is highly localised, due to it not having a written form it has much greater regional differences than speech. Regional accents are very strong, and international differences are extreme, with separate localised signing required for BSL, ASL and AUSLAN (British, American, Australian) for example, even though the original audio / captions would be almost identical.

Best practice example: Moss (autoplaying animated gif)