Audio problem: (May only apply to the original VHS release.) When Scar has Zazu locked up in a cage, Zazu mentions Mufasa's name and Scar yells at him, "What did you say?" Right before Scar's actual line, whilst Zazu is talking, you hear Scar's "What did you say?" line very faintly in the background, even though Zazu has not even mentioned Mufasa yet.
Audio problem: When Mufasa is clinging onto the rock after rescuing Simba and Scar is above him he says 'Scar brother help me'. If you listen very carefully he says the word 'brother' twice but his mouth only moves the second time he says it.
Audio problem: In the scene where Sarabi gives Simba and Nala permission to go to the waterhole, Simba yells "Yeah!" and you can distinctly hear that Nala says "all right!" But it's animated so both Cubs appear to be exclaiming "Yeah!"
Answer: Lions are not like humans, even though Disney tends to make them that way. It's rare for more than one or two full grown lions to be in a pride. Other males are in "bachelor prides" until they win a pride of their own. It's likely that Scar or Mufasa sired Nala.
Brenda Elzin