Only the Fairchild company in the 1960s was thinking about adding sound in a movie camera with an optical track, but never released a selling model; just made a prototype. Bell and Howell had the "Filmosound" using a cassette recorder synched with a camera which a friend of mine used. I did have the camera; a super 8mm model; the first one was defective in its shutter, the second ok, but the first one took better color movies then the second showing poor quality control.
Today however we have point and shoot cameras, some coming along with stereo sound at the prices my parents paid for a revere 8mm magazine camera or the likes. I have gotten splendid widescreen videos on some Panasonic units that I own with great mono sound quality though my specialty is ususally stereo for that opens the door to matrix surround sound when you shoot in stereo(dependent on the design and polar field of one's microphone in the camera). I really could have used this stuff in the 1960s.
ASI ES LA VIDA.