Others here are addressing technical solutions, but I don't see anyone here covering non-verbal communication. IMO, that's going to be just as important.
I am going to assume that your wife and you have a healthy relationship with strong communication, in part because you've developed an intuition for her body language and other non-verbal communication methods. In the scenario where she loses her ability to speak, even if she happily and completely takes to whatever technical solution(s) you offer to replace that, I think it's likely she will reflexively lean more heavily on those non-verbal channels, and you're going to need to get better at reading them than you are now.
I am going to assume that your wife and you have a healthy relationship with strong communication, in part because you've developed an intuition for her body language and other non-verbal communication methods. In the scenario where she loses her ability to speak, even if she happily and completely takes to whatever technical solution(s) you offer to replace that, I think it's likely she will reflexively lean more heavily on those non-verbal channels, and you're going to need to get better at reading them than you are now.