Recently I learned a little ASL for fun and during my rewatching of TNG I surprisingly(but it's not unreasonable) found out that in the episode Loud As A Whisper, Riva is actually using ASL(I know many of you know this but I didn't). One the one hand I'm glad that they didn't just use some random gesture and say it's sign language, and I love seeing ASL on TV and raise concern for deaf people. But on the other hand seeing a character who supposed to be an alien using ASL is just, I don't know, kinda strange. But I still like this idea. And I can see Brent Spiner tried hard to interpret but I can tell he didn't know the meaning so sometimes he interpret faster than he should be and sometimes he didn't sign all the words. I didn't expect that before learning ASL. But now understanding what they were signing really gives me extra fun to see this episode.
That's true but they explain that the whole universe speaks English because they have universal translator. But I love the idea of having deaf actor in the series