You can tell if your 16mm film reels have sound by checking the following:
Does the film have sprockets on both sides? Your film is silent if that is the case.
Does the film have yellow or rust-colored strips on one side and sprockets on the other? It’s possible that you have sound.
Does the side or edge have a translucent strip of varying width? You may have optical sound if this is the case.
Regular 8mm Film
A regular 8mm film does not have the option of a sound track and is silent instead.
Super 8mm Film
There may be sound in your Super 8 films if the reel has a thin yellow or rust-colored strip alongside the reel next to the sprockets and a thicker yellow-colored strip on the other edge of the reel. If this is the case then you have sound film with the potential of recorded sound.