Kanzi, a bonobo, is believed to understand more human language than any other non-human animal in the world. Kanzi apparently learned by eavesdropping on the keyboard lessons researcher Sue Savage-Rumbaugh was giving to his adoptive mother. Kanzi learned to communicate with a lexigram board, pushing symbols that stand for words. The board is wired to a computer, so the word is then vocalized out loud by the computer. This helps Kanzi develop his vocabulary and enables him to communicate with researchers.