Well, I think he should have given the kid a good English name, like Howard or Percival or Richard or something. Even making him a junior would have been acceptable. As it is...well, just imagine:

"Your Majesty, I would like to present my son, Korak (or Boy)."
"Thank you, Lord Greystoke. What an unusual name, young man. Does it have a special significance?"
"Yes, your majesty. It means "Killer" and was given to me by the Great Apes."

or

"Yes, your majesty. It was given to me by Hollywood and it means I'm a Boy."

By the way, "-nkani" is the stem for the Zulu "inkani" which means "stubborness or obstinancy." Closest I could find to the name of Tarzan's monkey.