I'm glad that they claimed not to know sign language. There's a tendency among the healthy and able-bodied (myself included) to assume that if someone is deaf or has a disability which prevents them from speaking then they've likely had it from birth and will have developed means of communicating in other ways.

But there are a slew of accidents and later-onset diseases which could leave someone suddenly unable to speak and without the time to learn to compensate with something like sign language.

When a close relative was diagnosed with one of these diseases in Australia, their doctor gave them a website to use where they could type and somebody would play their part on a phonecall. Their staff would call the desired number and transcribe the person's response, reading out in turn any (typed) response from my relative.

I don't know who ran or funded the service (likely local, state or federal government, because Australia is pretty good like that), or what it was called, but I have a great deal of respect for the program.