It was very apropos that I coincidently waited to watch this at Christmas time - not knowing that the final episode would be centered at Christmas. Had this on my watch list all this time and decided to watch the oldest one - for no other reason than that. I rate the acting 10 stars, especially the male lead Meguro Ren who played Sou, who I know absolutely nothing about, but thought that he did he great job portraying his emotions to the viewers through sign language, gazes, the looks on his face whether happy or sad and the personal struggles he is going through- not wanting to hurt others and getting hurt himself internally by wanting to remember his girlfriend's voice so much.
The lesson to be learned from this drama is that communicating is different from understanding especially when someone has a disability such as in Silent and we can all learn something from watching it and it is a touching a beautiful love story.
I had to take off a couple of stars because of the script made Kaho, who played the friend of Sou, absolutely annoying to me - always trying to but in with his former relationships at a critical time in his life.
Another thing that was annoying to me was the sound track of the series - not sure if this was intentional or not to get the point of silence across to the viewers, but practically on every scene change the sound (music playing or background noise, whatever) is cut-off abruptly for a couple of seconds of silence. I am thinking it is intentional to get your attention of what silence is like or something but I found it annoying and unpleasant to watch for that reason.