I genuinely can’t remember or not if your botw/totk link knows sign language or not…or am I thinking of a different link?

my personal headcanon is that he knows basic sign and uses it when he's completely nonverbal, but that for most of his time as a soldier pre-calamity he limits himself to basic signs that are well-known enough for anyone to understand and not much else (thank you, please, basic combat orders, occasional fingerspelling) and uses them VERY sparingly if at all. I personally believe that the lack of communication he displays pre-calamity goes beyond just physical muteness, and I think that removing the communication block by having him sign freely removes some of the nuance of his relationships with other people pre-calamity, so while i think he CAN sign, i think he only uses it when communication is absolutely necessary.