The current unmute button is "ativar som" (activate sound), so the wording was changed to "Seu som está desativado" (Your sound is deactivated -- sounds better in Portuguese than in english, trust me) to maintain a higher level of consistency through the interface and make the wording clearer, thus reducing possible user confusion.

I understand that the current mute button is "silenciar" (silence) across the app, but I believe options like "Você está silenciado" (you are silenced) would be somewhat ambiguous (eg. user might think they were muted by an admin) and hold a somewhat negative connotation to the user.