What is "kalulu"

Ndugu M’Hali or Kalulu (ca. 1865 – 28 March 1877) was an African slave and adopted child of the explorer and journalist Henry Morton Stanley. Kalulu died young but in his short life he visited Europe, America and the Seychelles. He had a book dedicated to him, a model in Madame Tussauds, and was a guest at Dr. Livingstone's funeral.