The movie was originally intended to be filmed in Iceland.
The language used by the cavemen, which comprises all of the spoken dialogue, was created by Anthony Burgess. Burgess is best known as the author of the novel and film A Clockwork Orange (1971), and creator of the language, Nadsat, used in it.
Desmond Morris choreographed the gestural and body language of the characters.
The special features and commentary state that there are only two species of hominids in the movie, Homo-sapiens and Neanderthal. Naoh and Ika are Homo-sapiens; however, the director commentary states that Ika's people are "more evolved". The other species, the Ape-like creatures, are representing Neanderthal man. If using the shooting locations as a reference; Naoh is from Scotland, Ika is from Kenya, and of course the Neanderthals are from Germany.
The title of this movie in French is "La Guerre du feu" and that is translated to "The War of fire", the German title is "Am anfang war das feuer" which means "At the beginning was the fire" and of course the English title is "Quest for fire". A trivial side note to this trivia, the fact that man living in such close proximity as Africa and on to England, France, and Germany yet all speak different languages reinforces the story line of the movie giving examples that early man was tribal and formed closed groups that depended on each other for survival.