I suspect that Jaws speaking at the end of MR was an idea that Lewis Gilbert came up with on the day of filming (with some egging from Sir Roger), long after Wood's script work had been completed. Nothing was said in the film TSWLM to confirm that Jaws was mute, so why not? Who's to say that Gilbert ever read that novelization?
Wood kept Jaws mute in his literary treatment of MR; not that it matters - the novel was almost as bonkers as the film, and I can't take either of them seriously.
I read one local critic who described Kabir Bedi as Kamal's 'hulking, apparently mute henchman." Fair enough, if you don't include the lines he spoke in Urdu - or English.
Some people thing all Bond henchmen are mute, just as they think that Goldfinger had a finger made of gold (hence his name, just like Bond's other nemeses Eyepatch, Hookhand and Duellingscar). With people like this you can only nod and pretend to agree, because they know their details, since they've "seen most of his movies, but they tend to blend together after a while - was that the one with the boats?"